{"title":"Yanmar 25HP 4-Stroke Marine Engine","description":"\u003csection id=\"hero\" style=\"padding:16px;border:1px solid #e5e7eb;border-radius:8px;max-width:1000px;margin:0 auto 18px;\"\u003e\n  \u003cp style=\"margin:0 0 12px;\"\u003eThis page is for Yanmar 4‑Stroke 25HP outboard engines. Use it to find compatible parts and service information, including maintenance tips, commonly replaced items, and troubleshooting guidance. You can also browse the main Yanmar collection. Scroll to the bottom of the page to start browsing parts for this engine, and on the collection page use the Filter \u0026amp; Sort controls to narrow results by horsepower, year range, and part category\/section.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar\" style=\"display:inline-block;padding:10px 14px;background:#0ea5e9;color:#fff;text-decoration:none;border-radius:6px;\"\u003eBrowse All Yanmar Parts\u003c\/a\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"identify-model\" style=\"max-width:1000px;margin:0 auto 22px;\"\u003e\n  \u003ch2\u003eHow to Identify Your 25HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eNameplate\/serial location: look on the transom bracket or mounting clamp; many outboards also have a sticker under the engine cowling.\u003c\/li\u003e\n    \u003cli\u003eModel code and suffix: letters often indicate shaft length (S\/L\/XL), starting method (manual\/electric), and control type (tiller\/remote). The serial number confirms year\/production run.\u003c\/li\u003e\n    \u003cli\u003ePlatform clues: most 25HP 4‑Stroke outboards are inline‑3. Older units are typically carbureted; newer units may be EFI. Fuel‑system type affects filters, sensors, and tuning parts.\u003c\/li\u003e\n    \u003cli\u003e4‑Stroke specifics: verify the oil filter style and service access layout; these can vary by year and control configuration.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"platforms\" style=\"max-width:1000px;margin:0 auto 22px;\"\u003e\n  \u003ch2\u003ePlatform Overview\u003c\/h2\u003e\n\n  \u003ch3 style=\"margin-top:10px;\"\u003eInline‑3 4‑Stroke (Carbureted)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #e5e7eb;padding:8px;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #e5e7eb;padding:8px;\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eInline‑3, SOHC 4‑Stroke, carbureted fuel system; manual or electric start; tiller or remote controls.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eCommon Models\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003e25HP 4‑Stroke carbureted variants (model suffixes differ by shaft length and controls).\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eAdvantages\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eSimple fuel system, serviceable jets, and straightforward diagnostics; solid reliability when maintained.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;\"\u003eNotes\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eCarburetor kits, fuel filters, and idle components are platform‑specific. Keep fuel fresh and consider a storage stabilizer to reduce varnish and deposits.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3 style=\"margin-top:18px;\"\u003eInline‑3 4‑Stroke (EFI)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #e5e7eb;padding:8px;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #e5e7eb;padding:8px;\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eInline‑3, SOHC 4‑Stroke with electronic fuel injection; ECM‑controlled fueling and ignition.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eCommon Models\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003e25HP EFI variants (verify model code for sensor and harness differences).\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eAdvantages\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eImproved cold starts, fuel economy, and emissions; less frequent carb cleaning; strong mid‑range torque.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;\"\u003eNotes\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eUse the correct micron‑rated fuel filter and maintain a healthy battery. Sensors (MAP, IAT, O2 if equipped) and harnesses are model‑specific.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"service-kits\" style=\"max-width:1000px;margin:0 auto 22px;\"\u003e\n  \u003ch2\u003eRoutine Maintenance \u0026amp; Service Parts\u003c\/h2\u003e\n  \u003cp style=\"margin:0 0 10px;\"\u003eIntervals below are general guidelines for 4‑Stroke outboards. Always follow the procedures and schedules in your official service manual.\u003c\/p\u003e\n  \u003ctable style=\"width:100%;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #e5e7eb;padding:8px;\"\u003eItem\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #e5e7eb;padding:8px;\"\u003eInterval*\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #e5e7eb;padding:8px;\"\u003eRemarks\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #e5e7eb;padding:8px;\"\u003eParts Link\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eEngine oil + filter\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eFirst 20 hours, then every 100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eWarm engine before draining; replace crush washer if applicable.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar-oil-filters\"\u003eYanmar Oil Filters\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eGear oil (lower unit)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eEvery 100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eCheck for metal or milky fluid; replace drain plug gaskets as needed.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar-service-maintenance-kits\"\u003eYanmar Service \u0026amp; Maintenance Kits\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eSpark plugs\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eInspect every 100 hours; replace as required\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eGap to spec; replace if fouled, worn, or corroded.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/spark-plug\"\u003eSpark Plugs\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eFuel filter \/ water separator\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eEvery 100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eUse the correct micron rating; drain bowls regularly if equipped.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar-fuel-filters\"\u003eYanmar Fuel Filters\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eWater pump impeller\/kit\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eEvery 2–3 seasons or 200 hours\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eReplace sooner if the tell‑tale is weak, after sandy\/silty use, or any overheat event.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/water-pump-impeller-rebuild-kits\"\u003eWater Pump Impeller Rebuild Kits\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eAnodes (sacrificial zincs)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eInspect every 50 hours; replace when 50% consumed\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eMatch anode material to your water (zinc for salt, aluminum\/magnesium for brackish\/fresh).\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/anodes\"\u003eAnodes\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;\"\u003eThermostat\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eInspect annually; replace if stuck or corroded\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eA weak thermostat can trigger overheat alarms or poor warm‑up.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar\"\u003eYanmar Collection\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n  \u003cp style=\"margin:8px 0 0;font-size:12px;color:#6b7280;\"\u003e*Intervals are typical for many 4‑Stroke outboards; confirm the exact schedule for your model and operating conditions.\u003c\/p\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"common-parts\" style=\"max-width:1000px;margin:0 auto 22px;\"\u003e\n  \u003ch2\u003eFrequently Used Parts Categories\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eRoutine Service: \u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar-service-maintenance-kits\"\u003eYanmar Service \u0026amp; Maintenance Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eOil \u0026amp; Filtration: \u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar-oil-filters\"\u003eYanmar Oil Filters\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eFuel System: \u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar-fuel-filters\"\u003eYanmar Fuel Filters\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eCooling System: \u003ca href=\"https:\/\/seasierra.com\/collections\/water-pumps\"\u003eWater Pumps\u003c\/a\u003e and \u003ca href=\"https:\/\/seasierra.com\/collections\/impellers\"\u003eImpellers\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eCorrosion Protection: \u003ca href=\"https:\/\/seasierra.com\/collections\/anodes\"\u003eAnodes\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eGaskets \u0026amp; Seals: \u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar-gaskets\"\u003eYanmar Gaskets\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eExhaust Components: \u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar-elbows\"\u003eYanmar Elbows\u003c\/a\u003e\n\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"troubleshooting\" style=\"max-width:1000px;margin:0 auto 22px;\"\u003e\n  \u003ch2\u003eCommon Symptoms \u0026amp; Quick Checks\u003c\/h2\u003e\n  \u003ctable style=\"width:100%;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #e5e7eb;padding:8px;\"\u003eSymptom\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #e5e7eb;padding:8px;\"\u003eCheck First\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #e5e7eb;padding:8px;\"\u003eRelated Parts\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eWeak tell‑tale or overheat alarm\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eInspect intake screens for blockage; verify water pump impeller condition; test thermostat.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eWater pump impeller kit, thermostat, intake screen\/grommets\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003ePoor acceleration \/ power loss\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eCheck prop damage or wrong pitch; confirm fresh fuel; replace\/inspect fuel filter; inspect plugs; verify throttle opening.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eFuel filter, spark plugs, propeller, air intake components\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eHard starting \/ rough idle\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eVerify battery voltage; inspect\/replace spark plugs; check for air leaks in fuel line; on carb units, clean idle circuits.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #f3f4f6;\"\u003eSpark plugs, fuel line\/primer bulb, fuel filter, carb kit (if applicable)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;\"\u003eGearcase noise or milky gear oil\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eDrain and inspect gear oil; check for fishing line on prop shaft; pressure test for leaking seals\/bearings.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;\"\u003eLower unit seal kit, bearings, drain plug gaskets, gear lube\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"faq\" style=\"max-width:1000px;margin:0 auto 22px;\"\u003e\n  \u003ch2\u003eFAQs\u003c\/h2\u003e\n  \u003cdetails style=\"margin-bottom:10px;\"\u003e\n    \u003csummary\u003eAre parts interchangeable between different years or platforms?\u003c\/summary\u003e\n    \u003cp\u003eMany routine service items (oil filters, anodes, some plugs) are shared, but fuel‑system, ignition, and control parts can differ by year, shaft length, starting method, and carb vs EFI platform. Always confirm by model code and serial number.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails style=\"margin-bottom:10px;\"\u003e\n    \u003csummary\u003eWhen should the water pump impeller be replaced?\u003c\/summary\u003e\n    \u003cp\u003eAs a rule of thumb, replace the impeller every 2–3 seasons or ~200 hours. Replace immediately after any overheat, weak tell‑tale, or heavy sand\/silt use.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails style=\"margin-bottom:10px;\"\u003e\n    \u003csummary\u003eHow often should I change lower unit gear oil?\u003c\/summary\u003e\n    \u003cp\u003eAt least once per season or every 100 hours. Check sooner if you notice shifting issues, noise, or water intrusion (fluid turns milky).\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat information helps confirm part compatibility?\u003c\/summary\u003e\n    \u003cp\u003eProvide the full model code, serial number, shaft length (S\/L\/XL), start type (manual\/electric), and control type (tiller\/remote). Photos of the nameplate and the part you’re replacing are also helpful.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"cta\" style=\"padding:16px;border:1px solid #e5e7eb;border-radius:8px;max-width:1000px;margin:0 auto 28px;\"\u003e\n  \u003cp style=\"margin:0 0 12px;\"\u003eReady to find parts for your Yanmar 25HP 4‑Stroke? Browse the main Yanmar collection and filter by horsepower, year, and category to zero in on the right components.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar\" style=\"display:inline-block;padding:10px 14px;background:#0ea5e9;color:#fff;text-decoration:none;border-radius:6px;\"\u003eShop Yanmar Parts\u003c\/a\u003e\n  \u003cp style=\"margin:8px 0 0;font-size:12px;color:#6b7280;\"\u003eIf you’re unsure about your model, send us a photo of the nameplate and the part you need and we’ll help verify compatibility.\u003c\/p\u003e\n\u003c\/section\u003e","products":[{"product_id":"exhaust-manifold-gasket-fits-yanmar-3jh-series-marine-diesel-engines-replaces-129150-13110","title":"Exhaust Manifold Gasket – Fits Yanmar 3JH Series Marine Diesel Engines (Replaces 129150-13110)","description":"\u003c!-- 🔧 Table Styles (include only once per page) --\u003e\n\u003cstyle\u003e\n  \/* Outer container allows horizontal scrolling (with iOS momentum) *\/\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n\n  \/* Base table styles *\/\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n\n  \/* Key: prevent wrapping, word breaks, and vertical text in headers *\/\n  table.ss-table th {\n    white-space:nowrap;       \/* Do not wrap *\/\n    word-break:normal;        \/* Don’t break words *\/\n    letter-spacing:normal;    \/* Prevent theme styles from stretching letters *\/\n    font-weight:600;\n    background:#f8fafc;\n  }\n\n  \/* Small screen optimization *\/\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\n\u003csection\u003e\n  \u003ch2\u003eProduct Details\u003c\/h2\u003e\n  \u003cp\u003eThis high-quality \u003cstrong\u003eExhaust Manifold Gasket\u003c\/strong\u003e is engineered to fit a wide range of Yanmar 3JH Series marine diesel engines, including the 3JH25A, 3JH30A, 3JH3E, 3JH4E, and 3JH5E models. It is fully compatible with both main and auxiliary engine applications, ensuring a reliable seal for the exhaust manifold connection.\u003c\/p\u003e\n  \u003cp\u003eThis part is a direct replacement for Yanmar OEM part number 129150-13110.\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eInstallation Method: Direct replacement\u003c\/li\u003e\n    \u003cli\u003ePrimary Application: Used on exhaust manifold connection\u003c\/li\u003e\n    \u003cli\u003eEngine Fuel Type: Diesel\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n  \u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n  \u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\u003c\/p\u003e\n  \u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003ePart Number\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e129150-13110\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n  \u003c\/div\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n  \u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n  \u003cp\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n  \u003cp\u003eThis gasket is designed for a broad range of Yanmar engines. Verify your specific model for an exact match.\u003c\/p\u003e\n  \u003cdiv class=\"ss-table-wrap\"\u003e\n    \u003ctable class=\"ss-table\" aria-label=\"Engine and Model Compatibility\"\u003e\n      \u003cthead\u003e\n        \u003ctr\u003e\n          \u003cth\u003eBrand\u003c\/th\u003e\n          \u003cth\u003eModel\u003c\/th\u003e\n          \u003cth\u003eRated HP\u003c\/th\u003e\n          \u003cth\u003eStroke\u003c\/th\u003e\n          \u003cth\u003eOEM Part No.\u003c\/th\u003e\n          \u003cth\u003eNotes\u003c\/th\u003e\n        \u003c\/tr\u003e\n      \u003c\/thead\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH25A\u003c\/td\u003e\n\u003ctd\u003e25\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003eUsed on fresh water cooler, keel cooler spec\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH30A\u003c\/td\u003e\n\u003ctd\u003e30\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003eUsed on fresh water cooler, keel cooler spec\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH2\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH2-TE\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH2BE\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH2TBE\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH3E\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH3E-YEU-E\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH4E\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH5E\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH5AE\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3TNV88F\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3GM30F\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3TNE84\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3TNV88-BDSA\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3TNV88\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3TN84L\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3TN84\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129150-13110\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n  \u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n  \u003cdl\u003e\n    \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eExhaust Manifold Gasket\u003c\/dd\u003e\n    \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect replacement\u003c\/dd\u003e\n    \u003cdt\u003eFuel Type\u003c\/dt\u003e\n\u003cdd\u003eDiesel\u003c\/dd\u003e\n    \u003cdt\u003eDimensions\u003c\/dt\u003e\n\u003cdd\u003e22.5\" L x 7.0\" W x 0.1\" H\u003c\/dd\u003e\n    \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eUsed on exhaust manifold connection\u003c\/dd\u003e\n  \u003c\/dl\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n  \u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003e1 x Gasket, Exhaust Manifold (129150-13110)\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n  \u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n  \u003col\u003e\n    \u003cli\u003eEnsure the engine is completely cool and the battery is disconnected before starting work.\u003c\/li\u003e\n    \u003cli\u003eCarefully remove the exhaust manifold, taking note of all connected components and fasteners.\u003c\/li\u003e\n    \u003cli\u003eThoroughly clean both the cylinder head and manifold mating surfaces. Remove all old gasket material and carbon buildup.\u003c\/li\u003e\n    \u003cli\u003ePosition the new gasket correctly, ensuring all bolt holes align perfectly.\u003c\/li\u003e\n    \u003cli\u003eReinstall the exhaust manifold and tighten the fasteners to the manufacturer's specified torque sequence and values.\u003c\/li\u003e\n    \u003cli\u003eReconnect any other components and the battery, then start the engine to check for exhaust leaks.\u003c\/li\u003e\n  \u003c\/ol\u003e\n\u003c\/section\u003e\n  \n\u003csection\u003e\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are the signs of a failing exhaust manifold gasket?\u003c\/summary\u003e\n  \u003cp\u003eCommon symptoms include a ticking or hissing sound from the engine bay (especially when cold), decreased engine performance, poor fuel economy, and the smell of exhaust fumes inside the cabin or cockpit.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWill this gasket fit my Yanmar 3GM30F engine?\u003c\/summary\u003e\n  \u003cp\u003eYes, this gasket is listed as compatible with the Yanmar 3GM30F model. However, always double-check the part number and visual appearance against your old part before installation.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eThe notes for my 3JH30A engine mention \"fresh water cooler spec.\" Is this the right gasket?\u003c\/summary\u003e\n  \u003cp\u003eYes. This part is primarily the exhaust manifold gasket, but on certain engine configurations like the 3JH30A with keel cooling, it also serves as a gasket for the cooler housing where it connects to the manifold assembly. It is the correct part for this application.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow often should this gasket be replaced?\u003c\/summary\u003e\n  \u003cp\u003eGaskets should be inspected during routine engine maintenance and replaced whenever the exhaust manifold is removed. There is no fixed replacement interval; replace it at the first sign of a leak to prevent further damage.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\n  \u003cp\u003eThis listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eShipping speed \u0026amp; cost?\u003c\/summary\u003e\n  \u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWarranty \u0026amp; returns?\u003c\/summary\u003e\n  \u003cp\u003eCovered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused \u0026amp; in original condition). See our policy page or reach out for instructions.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n  \u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eVerify images\/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.\u003c\/li\u003e\n    \u003cli\u003eThis is an aftermarket replacement, not an OEM component.\u003c\/li\u003e\n    \u003cli\u003eProfessional installation is recommended for safety and performance.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection\u003e\n  \u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003ePro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n    \u003cli\u003eFast Global Fulfillment — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n    \u003cli\u003eManufacturer-Direct Value — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50626123759931,"sku":"129150-13110","price":19.02,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/129150-13110_286f08c8-e4bb-42bf-8b73-6f37f15d05da.jpg?v=1759816329"},{"product_id":"front-seal-cover-gasket-fits-yanmar-3jh25a-marine-diesel-engines-replaces-129150-01531","title":"Front Seal Cover Gasket – Fits Yanmar 3JH25A Marine Diesel Engines (Replaces 129150-01531)","description":"\u003cstyle\u003e\n  \/* Outer container allows horizontal scrolling (with iOS momentum) *\/\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n\n  \/* Base table styles *\/\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n\n  \/* Key: prevent wrapping, word breaks, and vertical text in headers *\/\n  table.ss-table th {\n    white-space:nowrap;       \/* Do not wrap *\/\n    word-break:normal;        \/* Don’t break words *\/\n    letter-spacing:normal;    \/* Prevent theme styles from stretching letters *\/\n    font-weight:600;\n    background:#f8fafc;\n  }\n\n  \/* Small screen optimization *\/\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\u003csection\u003e\n  \u003ch2\u003eProduct Details\u003c\/h2\u003e\n  \u003cp\u003eThis is a direct replacement \u003cstrong\u003eFront Seal Cover Gasket\u003c\/strong\u003e designed to fit Yanmar 3JH25A 25 HP, 3-cylinder marine diesel engines manufactured between 1986–2012. It ensures a reliable seal for the front seal cover on the engine's gear housing.\u003c\/p\u003e\n  \u003cp\u003eThis part serves as an aftermarket equivalent for Yanmar OEM part number 129150-01531.\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eInstalls as a direct replacement for the original part.\u003c\/li\u003e\n    \u003cli\u003eSpecifically designed for the front seal cover on the engine gear housing.\u003c\/li\u003e\n    \u003cli\u003eMade from durable gasket material to prevent leaks and ensure longevity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n  \u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n  \u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\u003c\/p\u003e\n  \u003cdiv class=\"ss-table-wrap\"\u003e\n    \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n      \u003cthead\u003e\n        \u003ctr\u003e\n          \u003cth\u003eBrand\u003c\/th\u003e\n          \u003cth\u003ePart Number\u003c\/th\u003e\n        \u003c\/tr\u003e\n      \u003c\/thead\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eYanmar\u003c\/td\u003e\n          \u003ctd\u003e129150-01531\u003c\/td\u003e\n        \u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n  \u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n  \u003cp\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n  \u003cp\u003eThis part is compatible with select Yanmar marine diesel engines.\u003c\/p\u003e\n  \u003cdiv class=\"ss-table-wrap\"\u003e\n    \u003ctable class=\"ss-table\" aria-label=\"Engine \u0026amp; Model Compatibility\"\u003e\n      \u003cthead\u003e\n        \u003ctr\u003e\n          \u003cth\u003eBrand\u003c\/th\u003e\n          \u003cth\u003eModel\u003c\/th\u003e\n          \u003cth\u003eRated HP\u003c\/th\u003e\n          \u003cth\u003eStroke\u003c\/th\u003e\n          \u003cth\u003eYears\u003c\/th\u003e\n          \u003cth\u003eOEM Part No.\u003c\/th\u003e\n          \u003cth\u003eNotes\u003c\/th\u003e\n        \u003c\/tr\u003e\n      \u003c\/thead\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eYanmar\u003c\/td\u003e\n          \u003ctd\u003e3JH25A\u003c\/td\u003e\n          \u003ctd\u003e25\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e1986–2012\u003c\/td\u003e\n          \u003ctd\u003e129150-01531\u003c\/td\u003e\n          \u003ctd\u003e\u003c\/td\u003e\n        \u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n  \u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n  \u003cdl\u003e\n    \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eFront Seal Cover Gasket\u003c\/dd\u003e\n    \u003cdt\u003eApplication\u003c\/dt\u003e\n\u003cdd\u003eUsed for the front seal cover on engine gear housing\u003c\/dd\u003e\n    \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect replacement\u003c\/dd\u003e\n    \u003cdt\u003eFuel Type\u003c\/dt\u003e\n\u003cdd\u003eDiesel\u003c\/dd\u003e\n    \u003cdt\u003eMaterial\u003c\/dt\u003e\n\u003cdd\u003eGasket material (composition not specified)\u003c\/dd\u003e\n    \u003cdt\u003eDimensions\u003c\/dt\u003e\n\u003cdd\u003e24.0 cm x 21.0 cm x 0.1 cm\u003c\/dd\u003e\n  \u003c\/dl\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n  \u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cspan style=\"color:#d0021b;\"\u003e1\u003c\/span\u003e x Front Seal Cover Gasket (Replaces 129150-01531)\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n  \u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n  \u003col\u003e\n    \u003cli\u003eEnsure the engine is turned off, cool to the touch, and the battery is disconnected for safety.\u003c\/li\u003e\n    \u003cli\u003eLocate and access the engine's front seal cover. This may require removing other components.\u003c\/li\u003e\n    \u003cli\u003eCarefully remove the bolts securing the cover and detach it from the gear housing.\u003c\/li\u003e\n    \u003cli\u003eRemove the old gasket completely. Use a plastic scraper to avoid gouging the metal surfaces.\u003c\/li\u003e\n    \u003cli\u003eThoroughly clean both the housing and cover mating surfaces of any old gasket material, sealant, or oil.\u003c\/li\u003e\n    \u003cli\u003eEnsure both surfaces are clean, dry, and free from any scoring or damage before proceeding.\u003c\/li\u003e\n    \u003cli\u003ePosition the new gasket correctly onto the gear housing, ensuring all bolt holes are aligned.\u003c\/li\u003e\n    \u003cli\u003eRe-install the front seal cover and tighten the bolts in a crisscross pattern to the manufacturer's recommended torque specifications.\u003c\/li\u003e\n    \u003cli\u003eReconnect the battery, start the engine, and carefully inspect the cover area for any signs of oil leakage.\u003c\/li\u003e\n  \u003c\/ol\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n  \u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow do I know if this gasket fits my engine?\u003c\/summary\u003e\n    \u003cp\u003eThis gasket is specifically for the Yanmar 3JH25A model (25 HP, 1986–2012). Always verify your engine model and confirm it cross-references with the OEM part number 129150-01531 before ordering.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat are the signs of a failing front seal cover gasket?\u003c\/summary\u003e\n    \u003cp\u003eCommon symptoms include oil leaks from the front of the engine, typically around the gear housing or crankshaft pulley area. A visibly degraded, brittle, or cracked gasket is also a clear sign it needs replacement.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDo I need to use sealant with this gasket?\u003c\/summary\u003e\n    \u003cp\u003eTypically, this type of gasket is designed to be installed dry. However, always consult your engine's specific service manual, as some applications may recommend a thin, even layer of an appropriate sealant.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should this gasket be replaced?\u003c\/summary\u003e\n    \u003cp\u003eThere is no fixed replacement interval for this gasket. It should be replaced whenever the front seal cover is removed for service, or immediately if an oil leak is detected in that area.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\n    \u003cp\u003eThis listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eShipping speed \u0026amp; cost\u003c\/summary\u003e\n    \u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWarranty \u0026amp; returns\u003c\/summary\u003e\n    \u003cp\u003eCovered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused \u0026amp; in original condition). See our policy page or reach out for instructions.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n  \u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eVerify images\/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.\u003c\/li\u003e\n    \u003cli\u003eThis is an aftermarket replacement, not an OEM component.\u003c\/li\u003e\n    \u003cli\u003eProfessional installation is recommended for safety and performance.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n  \u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePro-Grade Standards\u003c\/strong\u003e — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFast Global Fulfillment\u003c\/strong\u003e — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50626124415291,"sku":"129150-01531","price":99.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/129150-01531_3e96a378-2edc-4da3-b8eb-caa78a5c449f.jpg?v=1759816352"},{"product_id":"cylinder-head-gasket-fits-yanmar-3jh-series-marine-engines-replaces-129171-01330","title":"Cylinder Head Gasket – Fits Yanmar 3JH Series Marine Engines (Replaces 129171-01330)","description":"\u003cstyle\u003e\n  \/* Outer container allows horizontal scrolling (with iOS momentum) *\/\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n\n  \/* Base table styles *\/\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n\n  \/* Key: prevent wrapping, word breaks, and vertical text in headers *\/\n  table.ss-table th {\n    white-space:nowrap;       \/* Do not wrap *\/\n    word-break:normal;        \/* Don’t break words *\/\n    letter-spacing:normal;    \/* Prevent theme styles from stretching letters *\/\n    font-weight:600;\n    background:#f8fafc;\n  }\n\n  \/* Small screen optimization *\/\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\u003csection\u003e\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis is a high-quality aftermarket \u003cstrong\u003eCylinder Head Gasket – Fits Yanmar 3JH Series Marine Engines (Replaces 129171-01330)\u003c\/strong\u003e, designed for 3-cylinder, 4-stroke marine diesel engines from the 1990s and 2000s. It ensures a reliable seal between the cylinder head and engine block.\u003c\/p\u003e\n\u003cp\u003eThis part is a direct replacement for Yanmar part number 129171-01330 and equivalent aftermarket references.\u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003eEngineered for direct-fit installation.\u003c\/li\u003e\n    \u003cli\u003eConstructed from durable multi-layer steel\/composite material.\u003c\/li\u003e\n    \u003cli\u003eMeets standard 1.4 mm thickness specification for a precise seal.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Cross-Reference\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003ePart Number\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAftermarket\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n\u003cp\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n\u003cp\u003eThis gasket fits a wide range of Yanmar 3JH series engines, including turbocharged and generator models.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Compatible Yanmar Engine Models\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003eModel\u003c\/th\u003e\n        \u003cth\u003eRated HP\u003c\/th\u003e\n        \u003cth\u003eStroke\u003c\/th\u003e\n        \u003cth\u003eOEM Part No.\u003c\/th\u003e\n        \u003cth\u003eNotes\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH2\u003c\/td\u003e\n        \u003ctd\u003e25-30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH25\u003c\/td\u003e\n        \u003ctd\u003e25\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH30\u003c\/td\u003e\n        \u003ctd\u003e30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH2(B)E\u003c\/td\u003e\n        \u003ctd\u003e25-30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH2BE\u003c\/td\u003e\n        \u003ctd\u003e25-30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH2E\u003c\/td\u003e\n        \u003ctd\u003e25-30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH2T(B)E\u003c\/td\u003e\n        \u003ctd\u003e25-30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003eTurbocharged model\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH2TBE\u003c\/td\u003e\n        \u003ctd\u003e25-30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003eTurbocharged model\u003c\/td\u003e\n      \u003c\/tr\u003e\n        \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH2TE\u003c\/td\u003e\n        \u003ctd\u003e25-30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003eTurbocharged model\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH2S-TBE\u003c\/td\u003e\n        \u003ctd\u003e25-30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003eSpecial turbocharged model\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH2G-TBE\u003c\/td\u003e\n        \u003ctd\u003e25-30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003eGenerator turbocharged model\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH2L-TNE\u003c\/td\u003e\n        \u003ctd\u003e25-30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003eLong-block turbocharged model\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3JH2Z\u003c\/td\u003e\n        \u003ctd\u003e25-30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e129171-01330\u003c\/td\u003e\n        \u003ctd\u003eGenerator application\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eCylinder Head Gasket\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect replacement\u003c\/dd\u003e\n  \u003cdt\u003eFuel Type\u003c\/dt\u003e\n\u003cdd\u003eDiesel\u003c\/dd\u003e\n  \u003cdt\u003eHousing Material\u003c\/dt\u003e\n\u003cdd\u003eMulti-layer steel\/composite\u003c\/dd\u003e\n  \u003cdt\u003eDimensions\u003c\/dt\u003e\n\u003cdd\u003e31.0 cm L x 16.0 cm W x 0.1 cm H\u003c\/dd\u003e\n  \u003cdt\u003eWeight\u003c\/dt\u003e\n\u003cdd\u003e0.5 kg (1.1 lb)\u003c\/dd\u003e\n  \u003cdt\u003eThickness\u003c\/dt\u003e\n\u003cdd\u003e1.4 mm\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e1 x Cylinder Head Gasket (129171-01330)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n    \u003cli\u003eDisconnect the battery and drain the engine coolant completely.\u003c\/li\u003e\n    \u003cli\u003eRemove the intake\/exhaust manifolds, valve cover, and rocker arm assembly.\u003c\/li\u003e\n    \u003cli\u003eLoosen and remove the cylinder head bolts in the reverse order of the manufacturer's specified torque sequence.\u003c\/li\u003e\n    \u003cli\u003eCarefully lift the cylinder head off the engine block.\u003c\/li\u003e\n    \u003cli\u003eRemove the old gasket and thoroughly clean both mating surfaces of any old gasket material or debris.\u003c\/li\u003e\n    \u003cli\u003ePosition the new gasket correctly on the engine block; check for any \"TOP\" or \"FRONT\" markings.\u003c\/li\u003e\n    \u003cli\u003eReinstall the cylinder head. Lubricate and install the head bolts, tightening them in stages according to the official torque sequence and specifications.\u003c\/li\u003e\n    \u003cli\u003eReassemble the rocker arms, manifolds, and all other components removed.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I know if this gasket fits my Yanmar engine?\u003c\/summary\u003e\n  \u003cp\u003eThis gasket is specifically designed for the Yanmar 3JH series, including models like the 3JH2, 3JH25, and various turbo versions. To ensure a perfect match, please verify that your engine model is on our compatibility list and that the part number you are replacing is 129171-01330.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are the signs of a failed cylinder head gasket?\u003c\/summary\u003e\n  \u003cp\u003eCommon symptoms of a blown head gasket include engine overheating, white smoke from the exhaust (indicating burning coolant), milky or frothy engine oil (coolant mixing with oil), loss of power, or poor engine compression.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this gasket thicker or thinner than the original?\u003c\/summary\u003e\n  \u003cp\u003eThis gasket has a standard thickness of 1.4 mm, which matches the OEM specification for most Yanmar 3JH applications. Always consult your engine's service manual to confirm the required gasket thickness, especially if the head or block has been machined.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eCan I reuse my old cylinder head gasket?\u003c\/summary\u003e\n  \u003cp\u003eNo. Cylinder head gaskets are \"crush\" type gaskets designed for one-time use. They deform to create a perfect seal and must be replaced every time the cylinder head is removed to ensure engine integrity.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\n  \u003cp\u003eThis listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eShipping speed \u0026amp; cost\u003c\/summary\u003e\n  \u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWarranty \u0026amp; returns\u003c\/summary\u003e\n  \u003cp\u003eCovered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused \u0026amp; in original condition). See our policy page or reach out for instructions.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eVerify images\/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.\u003c\/li\u003e\n  \u003cli\u003eThis is an aftermarket replacement, not an OEM component.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended for safety and performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePro-Grade Standards\u003c\/strong\u003e — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFast Global Fulfillment\u003c\/strong\u003e — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50626125332795,"sku":"129171-01330","price":99.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/CylinderHeadGasket_FitsYanmar3JHSeriesMarineEngines_Replaces129171-01330.jpg?v=1762820182"},{"product_id":"oil-pump-gasket-fits-yanmar-3jh-4jh-series-marine-diesel-engines-replaces-129150-35042","title":"Oil Pump Gasket – Fits Yanmar 3JH \u0026 4JH Series Marine Diesel Engines (Replaces 129150-35042)","description":"\u003cstyle\u003e\n  \/* Outer container allows horizontal scrolling (with iOS momentum) *\/\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n\n  \/* Base table styles *\/\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n\n  \/* Key: prevent wrapping, word breaks, and vertical text in headers *\/\n  table.ss-table th {\n    white-space:nowrap;       \/* Do not wrap *\/\n    word-break:normal;        \/* Don’t break words *\/\n    letter-spacing:normal;    \/* Prevent theme styles from stretching letters *\/\n    font-weight:600;\n    background:#f8fafc;\n  }\n\n  \/* Small screen optimization *\/\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\u003csection\u003e\n    \u003ch2\u003eProduct Details\u003c\/h2\u003e\n    \u003cp\u003eThis high-quality aftermarket \u003cstrong\u003eOil Pump Gasket\u003c\/strong\u003e is engineered for a precise fit on a range of Yanmar 3JH and 4JH Series marine diesel engines. It provides a reliable, leak-proof seal, ensuring optimal performance and longevity for your engine's lubrication system.\u003c\/p\u003e\n    \u003cp\u003eIt serves as a direct replacement for Yanmar OEM part number 129150-35042.\u003c\/p\u003e\n    \u003cul\u003e\n        \u003cli\u003eInstalls as a direct OEM-equivalent replacement.\u003c\/li\u003e\n        \u003cli\u003eMade from premium, heat-resistant, non-asbestos material.\u003c\/li\u003e\n        \u003cli\u003eEngineered to create a durable, leak-proof oil pump seal.\u003c\/li\u003e\n    \u003c\/ul\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n    \u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n    \u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\u003c\/p\u003e\n    \u003cdiv class=\"ss-table-wrap\"\u003e\n        \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n            \u003cthead\u003e\n                \u003ctr\u003e\n                    \u003cth\u003eBrand\u003c\/th\u003e\n                    \u003cth\u003ePart Number\u003c\/th\u003e\n                \u003c\/tr\u003e\n            \u003c\/thead\u003e\n            \u003ctbody\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                \u003c\/tr\u003e\n            \u003c\/tbody\u003e\n        \u003c\/table\u003e\n    \u003c\/div\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n    \u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n    \u003cp\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n    \u003cp\u003eThis gasket is compatible with the following Yanmar 3JH and 4JH series marine diesel engines.\u003c\/p\u003e\n    \u003cdiv class=\"ss-table-wrap\"\u003e\n        \u003ctable class=\"ss-table\" aria-label=\"Engine \u0026amp; Model Compatibility\"\u003e\n            \u003cthead\u003e\n                \u003ctr\u003e\n                    \u003cth\u003eBrand\u003c\/th\u003e\n                    \u003cth\u003eModel\u003c\/th\u003e\n                    \u003cth\u003eRated HP\u003c\/th\u003e\n                    \u003cth\u003eStroke\u003c\/th\u003e\n                    \u003cth\u003eYears\u003c\/th\u003e\n                    \u003cth\u003eOEM Part No.\u003c\/th\u003e\n                    \u003cth\u003eNotes\u003c\/th\u003e\n                \u003c\/tr\u003e\n            \u003c\/thead\u003e\n            \u003ctbody\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e3JH25A\u003c\/td\u003e\n                    \u003ctd\u003e25\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e3JH40\u003c\/td\u003e\n                    \u003ctd\u003e40\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e3JH4E\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH-HTBE\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH-TE\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH110\u003c\/td\u003e\n                    \u003ctd\u003e110\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH2\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH3-DTE\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH3-HTE\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH3-TE\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH3E\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH4-DTE\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH45\u003c\/td\u003e\n                    \u003ctd\u003e45\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH4AE\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH4E\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH57\u003c\/td\u003e\n                    \u003ctd\u003e57\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH5E\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n                \u003ctr\u003e\n                    \u003ctd\u003eYanmar\u003c\/td\u003e\n                    \u003ctd\u003e4JH80\u003c\/td\u003e\n                    \u003ctd\u003e80\u003c\/td\u003e\n                    \u003ctd\u003e4-Stroke\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                    \u003ctd\u003e129150-35042\u003c\/td\u003e\n                    \u003ctd\u003e\u003c\/td\u003e\n                \u003c\/tr\u003e\n            \u003c\/tbody\u003e\n        \u003c\/table\u003e\n    \u003c\/div\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n    \u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n    \u003cdl\u003e\n        \u003cdt\u003eProduct Type\u003c\/dt\u003e\n        \u003cdd\u003eOil Pump Gasket\u003c\/dd\u003e\n        \u003cdt\u003eInstallation\u003c\/dt\u003e\n        \u003cdd\u003eDirect OEM replacement\u003c\/dd\u003e\n        \u003cdt\u003eHousing Material\u003c\/dt\u003e\n        \u003cdd\u003ePremium heat-resistant material (non-asbestos)\u003c\/dd\u003e\n        \u003cdt\u003eDimensions\u003c\/dt\u003e\n        \u003cdd\u003e5.0\" x 5.0\" x 0.1\"\u003c\/dd\u003e\n        \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n        \u003cdd\u003eEngineered for leak-proof oil pump seal\u003c\/dd\u003e\n    \u003c\/dl\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n    \u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n    \u003cul\u003e\n        \u003cli\u003e\n\u003cspan style=\"color:#d0021b;\"\u003e1\u003c\/span\u003e x Oil Pump Gasket (Replaces 129150-35042)\u003c\/li\u003e\n    \u003c\/ul\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n    \u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n    \u003col\u003e\n        \u003cli\u003eDisconnect the battery and ensure the engine is cool.\u003c\/li\u003e\n        \u003cli\u003eDrain the engine oil completely into a suitable container.\u003c\/li\u003e\n        \u003cli\u003eRemove any components obstructing access to the oil pump assembly.\u003c\/li\u003e\n        \u003cli\u003eCarefully unbolt and remove the oil pump from the engine block.\u003c\/li\u003e\n        \u003cli\u003eRemove the old gasket. Thoroughly clean both the engine and pump mating surfaces, ensuring they are free of old debris, oil, and sealant.\u003c\/li\u003e\n        \u003cli\u003ePosition the new gasket correctly on the oil pump or engine block.\u003c\/li\u003e\n        \u003cli\u003eReinstall the oil pump, ensuring it is properly aligned. Tighten bolts in a crisscross pattern to the manufacturer's recommended torque specifications.\u003c\/li\u003e\n        \u003cli\u003eReassemble any components that were removed.\u003c\/li\u003e\n        \u003cli\u003eRefill the engine with the correct grade and amount of fresh oil.\u003c\/li\u003e\n        \u003cli\u003eReconnect the battery, start the engine, and carefully inspect for any oil leaks around the pump housing.\u003c\/li\u003e\n    \u003c\/ol\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n    \u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n    \u003cdetails\u003e\n        \u003csummary\u003eHow do I confirm this gasket fits my specific Yanmar engine?\u003c\/summary\u003e\n        \u003cp\u003eThis gasket is designed for Yanmar's 3JH and 4JH series engines. The most reliable method is to check our Engine \u0026amp; Model Compatibility table to see if your model is listed. Always cross-reference the OEM part number (129150-35042) with your engine's service manual to ensure an exact match.\u003c\/p\u003e\n    \u003c\/details\u003e\n    \u003cdetails\u003e\n        \u003csummary\u003eWhat are the common signs of a failing oil pump gasket?\u003c\/summary\u003e\n        \u003cp\u003eThe most common symptom is a visible oil leak originating from the seam where the oil pump meets the engine block. Other signs can include a gradual drop in engine oil levels, unexplained low oil pressure warnings, or oil residue on surrounding engine components.\u003c\/p\u003e_\n    \u003c\/details\u003e\n    \u003cdetails\u003e\n        \u003csummary\u003eShould I use sealant or gasket adhesive with this part?\u003c\/summary\u003e\n        \u003cp\u003eIn most cases, this gasket is designed to be installed dry on clean, flat surfaces. However, always refer to your engine's specific service manual. Some applications or slightly imperfect surfaces might call for a very thin layer of an appropriate oil-resistant sealant.\n    \u003cdetails\u003e\n        \u003csummary\u003eWhen should this gasket be replaced?\u003c\/summary\u003e\n        \u003cp\u003eThe oil pump gasket is not a routine replacement item. It should be replaced anytime the oil pump is removed for service, or immediately if you detect a leak in that area.\u003c\/p\u003e\n    \u003c\/details\u003e\n    \u003cdetails\u003e\n        \u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\n        \u003cp\u003eThis listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.\u003c\/p\u003e\n    \u003c\/details\u003e\n    \u003cdetails\u003e\n        \u003csummary\u003eShipping speed \u0026amp; cost\u003c\/summary\u003e\n        \u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\n    \u003c\/details\u003e\n    \u003cdetails\u003e\n        \u003csummary\u003eWarranty \u0026amp; returns\u003c\/summary\u003e\n        \u003cp\u003eCovered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused \u0026amp; in original condition). See our policy page or reach out for instructions.\u003c\/p\u003e\n    \u003c\/details\u003e\n\u003c\/p\u003e\u003c\/details\u003e\u003c\/section\u003e\n\u003csection\u003e\n    \u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n    \u003cul\u003e\n        \u003cli\u003eVerify images\/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.\u003c\/li\u003e\n        \u003cli\u003eThis is an aftermarket replacement, not an OEM component.\u003c\/li\u003e\n        \u003cli\u003eProfessional installation is recommended for safety and performance.\u003c\/li\u003e\n    \u003c\/ul\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n    \u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n    \u003cul\u003e\n        \u003cli\u003e\n\u003cstrong\u003ePro-Grade Standards\u003c\/strong\u003e — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eFast Global Fulfillment\u003c\/strong\u003e — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n        \u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n    \u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50626126250299,"sku":"129150-35042","price":13.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/129150-35042_b8527f44-badd-4130-a22f-291ce3709e77.png?v=1759816431"},{"product_id":"gasket-cover-fits-yanmar-3jh25a-3jh30a-marine-engines-replaces-129100-01621","title":"Gasket, Cover – Fits Yanmar 3JH25A\/3JH30A Marine Engines (Replaces 129100-01621)","description":"\u003cstyle\u003e\n  \/* Outer container allows horizontal scrolling (with iOS momentum) *\/\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n\n  \/* Base table styles *\/\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n\n  \/* Key: prevent wrapping, word breaks, and vertical text in headers *\/\n  table.ss-table th {\n    white-space:nowrap;       \/* Do not wrap *\/\n    word-break:normal;        \/* Don’t break words *\/\n    letter-spacing:normal;    \/* Prevent theme styles from stretching letters *\/\n    font-weight:600;\n    background:#f8fafc;\n  }\n\n  \/* Small screen optimization *\/\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\u003csection\u003e\n  \u003ch2\u003eProduct Details\u003c\/h2\u003e\n  \u003cp\u003eThis is a high-quality replacement \u003cstrong\u003eGasket, Cover – Fits Yanmar 3JH25A\/3JH30A Marine Engines (Replaces 129100-01621)\u003c\/strong\u003e, designed to provide a proper seal for the engine's rear seal cover assembly. It is engineered to meet or exceed original manufacturer specifications, ensuring reliable performance in marine environments.\u003c\/p\u003e\n  \u003cp\u003eThis part is a direct replacement for Yanmar part number 129100-01621.\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eInstallation Method: Direct replacement\u003c\/li\u003e\n    \u003cli\u003eEngineered for marine diesel applications\u003c\/li\u003e\n    \u003cli\u003eIncludes one cover gasket\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n  \u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\u003c\/p\u003e\n  \u003cdiv class=\"ss-table-wrap\"\u003e\n    \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n      \u003cthead\u003e\n        \u003ctr\u003e\n          \u003cth\u003eBrand\u003c\/th\u003e\n          \u003cth\u003ePart Number\u003c\/th\u003e\n        \u003c\/tr\u003e\n      \u003c\/thead\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eYanmar\u003c\/td\u003e\n          \u003ctd\u003e129100-01621\u003c\/td\u003e\n        \u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\n  \u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n  \u003cp\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n  \u003cdiv class=\"ss-table-wrap\"\u003e\n    \u003ctable class=\"ss-table\" aria-label=\"Engine \u0026amp; Model Compatibility\"\u003e\n      \u003cthead\u003e\n        \u003ctr\u003e\n          \u003cth\u003eBrand\u003c\/th\u003e\n          \u003cth\u003eModel\u003c\/th\u003e\n          \u003cth\u003eRated HP\u003c\/th\u003e\n          \u003cth\u003eStroke\u003c\/th\u003e\n          \u003cth\u003eOEM Part No.\u003c\/th\u003e\n          \u003cth\u003eNotes\u003c\/th\u003e\n        \u003c\/tr\u003e\n      \u003c\/thead\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eYanmar\u003c\/td\u003e\n          \u003ctd\u003e3JH25A\u003c\/td\u003e\n          \u003ctd\u003e25\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e129100-01621\u003c\/td\u003e\n          \u003ctd\u003e\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n          \u003ctd\u003eYanmar\u003c\/td\u003e\n          \u003ctd\u003e3JH30A\u003c\/td\u003e\n          \u003ctd\u003e30\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e129100-01621\u003c\/td\u003e\n          \u003ctd\u003e\u003c\/td\u003e\n        \u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\n  \u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n  \u003cdl\u003e\n    \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eGasket, Rear Seal Cover\u003c\/dd\u003e\n    \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect replacement\u003c\/dd\u003e\n    \u003cdt\u003eHousing Material\u003c\/dt\u003e\n\u003cdd\u003ePaper\/Composite\u003c\/dd\u003e\n    \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eOriginal manufacturer specification\u003c\/dd\u003e\n    \u003cdt\u003eProduct Dimensions\u003c\/dt\u003e\n\u003cdd\u003e21.0cm L x 20.0cm W x 0.1cm H\u003c\/dd\u003e\n  \u003c\/dl\u003e\n\n  \u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003e1 x Gasket, Cover (129100-01621)\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n  \u003col\u003e\n    \u003cli\u003eDisconnect the negative battery terminal to prevent accidental shorts.\u003c\/li\u003e\n    \u003cli\u003eIf necessary, drain engine oil or coolant to avoid spills when the cover is removed.\u003c\/li\u003e\n    \u003cli\u003eRemove any components obstructing access to the rear seal cover.\u003c\/li\u003e\n    \u003cli\u003eCarefully unbolt and remove the cover. The old gasket may be stuck to the cover or the engine block.\u003c\/li\u003e\n    \u003cli\u003eThoroughly clean both mating surfaces. Use a plastic scraper and appropriate solvent to remove all traces of old gasket material and sealant without scratching the metal.\u003c\/li\u003e\n    \u003cli\u003ePosition the new gasket correctly on the engine block or cover, aligning all bolt holes.\u003c\/li\u003e\n    \u003cli\u003eReinstall the cover and tighten the bolts in a crossing pattern to the manufacturer's specified torque to ensure even pressure.\u003c\/li\u003e\n    \u003cli\u003eReinstall any components that were removed. Refill drained fluids.\u003c\/li\u003e\n    \u003cli\u003eReconnect the battery, start the engine, and carefully inspect for any leaks around the cover.\u003c\/li\u003e\n  \u003c\/ol\u003e\n\n  \u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow can I confirm this gasket fits my Yanmar engine?\u003c\/summary\u003e\n    \u003cp\u003eThis gasket is a direct fit for Yanmar models 3JH25A and 3JH30A. Verify your engine model and cross-reference the OEM part number 129100-01621. Visually comparing your old gasket to the product images is also a reliable confirmation step.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat are common signs of a failed rear seal cover gasket?\u003c\/summary\u003e\n    \u003cp\u003eThe most common sign of a failed gasket is an oil leak from the area where the rear seal cover meets the engine block. You may notice oil drips under the engine or an accumulation of grime and oil on the housing itself.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDoes this gasket require any sealant during installation?\u003c\/summary\u003e\n    \u003cp\u003eTypically, paper or composite gaskets like this one are designed to be installed dry. However, always consult your engine's service manual. Some applications may recommend a very thin coat of a specific gasket sealant or tackifier to hold it in place during assembly.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should this gasket be replaced?\u003c\/summary\u003e\n    \u003cp\u003eThis gasket does not have a set replacement interval. It should be replaced whenever the rear seal cover is removed for service, or if it shows signs of leaking.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\n    \u003cp\u003eThis listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eShipping speed \u0026amp; cost\u003c\/summary\u003e\n    \u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWarranty \u0026amp; returns\u003c\/summary\u003e\n    \u003cp\u003eCovered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused \u0026amp; in original condition). See our policy page or reach out for instructions.\u003c\/p\u003e\n  \u003c\/details\u003e\n\n  \u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eVerify images\/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.\u003c\/li\u003e\n    \u003cli\u003eThis is an aftermarket replacement, not an OEM component.\u003c\/li\u003e\n    \u003cli\u003eProfessional installation is recommended for safety and performance.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePro-Grade Standards\u003c\/strong\u003e — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFast Global Fulfillment\u003c\/strong\u003e — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50626126512443,"sku":"129100-01621","price":99.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/129100-01621_1b1a8b2e-88eb-48ad-a4dc-27e4dc10bd05.jpg?v=1759816435"}],"url":"https:\/\/seasierra.com\/collections\/yanmar-25hp-4-stroke-marine-engine.oembed","provider":"SeaSierra","version":"1.0","type":"link"}