{"title":"Yanmar 4-Stroke 24HP Marine Engine Parts","description":"\u003csection id=\"hero\" style=\"padding:16px; border:1px solid #e3e3e3; border-radius:8px;\"\u003e\n  \u003cp\u003eThis page is dedicated to Yanmar 4-Stroke 24HP outboard engines. Use it to find compatible parts and practical service information. Below you’ll find maintenance tips, common replacement parts, and troubleshooting guidance. You can also browse our main Yanmar collection. Scroll down to the bottom of this page to start browsing parts for this engine. On collection pages, use the Filter \u0026amp; Sort controls to narrow results by horsepower, year range, and part category.\u003c\/p\u003e\n  \u003cp\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar\" style=\"display:inline-block; padding:10px 16px; background:#0a5; color:#fff; text-decoration:none; border-radius:6px;\"\u003eBrowse All Yanmar Parts\u003c\/a\u003e\u003c\/p\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"identify-model\" style=\"margin-top:24px;\"\u003e\n  \u003ch2\u003eHow to Identify Your 24HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eLocate the nameplate\/serial plate on the clamp bracket or swivel bracket. It typically shows the model code, serial number, and production details.\u003c\/li\u003e\n    \u003cli\u003eRead the model suffix: it often indicates shaft length (S\/L\/XL), control type (tiller vs. remote), and minor year or revision codes.\u003c\/li\u003e\n    \u003cli\u003eConfirm 4-stroke indicators such as an engine oil dipstick and filler cap; these help distinguish 4-stroke from older 2-stroke units.\u003c\/li\u003e\n    \u003cli\u003eNote any intake or cowling differences that separate carbureted vs. EFI variants; this can affect fuel system and electrical parts selection.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"engine-overview\" style=\"margin-top:24px;\"\u003e\n  \u003ch2\u003eEngine Overview\u003c\/h2\u003e\n  \u003ch3\u003e24–25 HP Class 4‑Stroke Outboard\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 #ddd; padding:8px;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; 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 #eee;\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eTypically inline 2–3 cylinder, 4-stroke, carbureted or EFI depending on year; manual or electric start; tiller or remote control.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eCommon Models\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eExamples in the 24–25 HP class with short\/long shaft variants; verify exact model code and suffix on the serial plate before ordering.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eAdvantages\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eQuiet operation, good fuel economy, reliable low‑to‑mid‑range torque for small craft and tenders.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eNotes\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eSome parts differ by shaft length, control style, and fuel system (carb vs. EFI). Always match parts to your exact model and serial number.\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=\"margin-top:24px;\"\u003e\n  \u003ch2\u003eRoutine Maintenance \u0026amp; Service Parts\u003c\/h2\u003e\n  \u003cp\u003eIntervals below are general guidelines for 4‑stroke outboards. Always follow your specific service manual for procedures and torque specs.\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 #ddd; padding:8px;\"\u003eItem\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eInterval*\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eRemarks\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; 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 #eee;\"\u003eEngine oil + filter\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eFirst 20 hrs, then every 100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eWarm engine before draining; replace crush washer if applicable; confirm oil grade.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\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 #eee;\"\u003eGear oil (lower unit)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eEvery 100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eInspect for water intrusion (milky oil) and metal debris; replace seals if needed.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/lower-unit-seal-kits\"\u003eLower Unit Seal Kits\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eSpark plugs\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eInspect every 100 hrs; replace as needed\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eCheck gap and color; replace if fouled, worn, or out of spec.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/spark-plug\"\u003eSpark plug\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eFuel filter \/ water-separating filter\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eEvery 100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eDrain\/replace sooner if contaminated fuel is suspected.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\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 #eee;\"\u003eWater pump impeller \/ kit\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eEvery 2 seasons or 200 hrs (whichever comes first)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eReplace sooner if weak tell‑tale or overheat alarm occurs; inspect housing and key.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\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 #eee;\"\u003eAnodes (internal\/external)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eInspect every 50 hrs; replace when 50% consumed\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eMatch anode material to water type (salt\/brackish\/fresh) and keep mounting surfaces clean.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/anodes\"\u003eAnodes\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n  \u003cp style=\"font-size:12px; color:#555;\"\u003e*Intervals are general guidelines; consult your model’s service schedule for exact requirements.\u003c\/p\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"common-parts\" style=\"margin-top:24px;\"\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\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\u003eFuel System: \u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar-fuel-filters\"\u003eFuel filters\u003c\/a\u003e and \u003ca href=\"https:\/\/seasierra.com\/collections\/fuel-pumps\"\u003eFuel Pumps\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eIgnition \/ Electrical: \u003ca href=\"https:\/\/seasierra.com\/collections\/electrical-items\"\u003eElectrical Items\u003c\/a\u003e and \u003ca href=\"https:\/\/seasierra.com\/collections\/rectifiers\"\u003eRectifiers\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\u003ePropulsion: \u003ca href=\"https:\/\/seasierra.com\/collections\/propellers\"\u003ePropellers\u003c\/a\u003e and \u003ca href=\"https:\/\/seasierra.com\/collections\/propeller-guards\"\u003ePropeller Guards\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eGearcase Sealing: \u003ca href=\"https:\/\/seasierra.com\/collections\/lower-unit-seal-kits\"\u003eLower Unit Seal Kits\u003c\/a\u003e\n\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"troubleshooting\" style=\"margin-top:24px;\"\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 #ddd; padding:8px;\"\u003eSymptom\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; padding:8px;\"\u003eCheck First\u003c\/th\u003e\n        \u003cth style=\"text-align:left; border-bottom:1px solid #ddd; 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 #eee;\"\u003eWeak tell‑tale or overheat alarm\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eInspect intake screen for blockage, verify pump prime, check impeller condition and thermostat.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eWater pump impeller kit, thermostat, intake screen, gaskets\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003ePoor acceleration or power loss\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eCheck prop for damage\/cavitation, inspect spark plugs, replace fuel filter, confirm clean fuel and proper venting.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003ePropeller, spark plugs, fuel filter, fuel pump\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eHard starting or rough idle\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eVerify fresh fuel, inspect\/replace plugs, check idle air passages and for vacuum leaks; on EFI, confirm battery health.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eSpark plugs, fuel filter, gaskets, electrical\/charging components\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eGearcase noise or metal in gear oil\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eDrain lube and inspect; pressure\/vacuum test gearcase; check for seal damage and bearing wear.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eLower unit seal kit, shims\/seals, bearings\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eBattery not charging\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eTest battery voltage, inspect connections\/grounds, check rectifier‑regulator output.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px; border-bottom:1px solid #eee;\"\u003eRectifier\/regulator, electrical connectors, wiring\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=\"margin-top:24px;\"\u003e\n  \u003ch2\u003eFAQs\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eAre parts interchangeable between different years or platforms?\u003c\/summary\u003e\n    \u003cp\u003eSome components interchange, but many items differ by model code, fuel system (carb vs. EFI), and shaft length. Always match parts to the exact model and serial number on your nameplate.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhen should the impeller be replaced?\u003c\/summary\u003e\n    \u003cp\u003eAs a preventive measure, replace the impeller every 2 seasons or ~200 hours, and sooner if you see a weak tell‑tale, overheat warnings, or sand\/silt usage.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should I change gear oil?\u003c\/summary\u003e\n    \u003cp\u003eChange lower unit gear oil every 100 hours or annually. If water contamination (milky oil) or metal debris is present, diagnose and reseal the gearcase before further use.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat information do you need to confirm part compatibility?\u003c\/summary\u003e\n    \u003cp\u003ePlease provide the full model code, serial number, shaft length, control type, and any visible carb\/EFI identifiers. Photos of the nameplate and the part needing replacement are very helpful.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"cta\" style=\"margin-top:24px; padding:16px; border:1px solid #e3e3e3; border-radius:8px;\"\u003e\n  \u003cp\u003eReady to find the right components? Browse the main Yanmar collection and use Filter \u0026amp; Sort to narrow by horsepower, year, and model.\u003c\/p\u003e\n  \u003cp\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yanmar\" style=\"display:inline-block; padding:10px 16px; background:#0a5; color:#fff; text-decoration:none; border-radius:6px;\"\u003eShop Yanmar Parts\u003c\/a\u003e\u003c\/p\u003e\n  \u003cp style=\"font-size:12px; color:#555;\"\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":"cylinder-head-gasket-fits-yanmar-3gm30-series-marine-diesel-engines-replaces-128374-01911","title":"Cylinder Head Gasket – Fits Yanmar 3GM30 Series Marine Diesel Engines (Replaces 128374-01911)","description":"\u003csection\u003e\n\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\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis high-quality \u003cstrong\u003eCylinder Head Gasket – Fits Yanmar 3GM30 Series\u003c\/strong\u003e is engineered for 24–27 HP, 3-cylinder, 4-stroke marine diesel engines, including popular models like the 3GM30, 3GM30F, and their variants. It creates a critical, durable seal between the cylinder head and the engine block to prevent combustion gas leaks and coolant or oil intrusion.\u003c\/p\u003e\n\u003cp\u003eThis part is a direct cross-reference for Yanmar OEM part 128374-01911 and aftermarket equivalents such as JSK YMAF5077 and YMAF5239.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eInstallation: Designed as a drop-in component for engine repair and rebuilds.\u003c\/li\u003e\n  \u003cli\u003eMaterial: Constructed from high-temperature composite materials to withstand extreme pressures and temperatures.\u003c\/li\u003e\n  \u003cli\u003eBore Size: Precision-cut for a 75 mm engine bore.\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\u003e128374-01911\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eJSK\u003c\/td\u003e\n        \u003ctd\u003eYMAF5077\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eJSK\u003c\/td\u003e\n        \u003ctd\u003eYMAF5239\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 is specifically designed for various Yanmar 3GM30 series marine 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\u003eOEM Part No.\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\u003e3GM30\u003c\/td\u003e\n        \u003ctd\u003e24\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e128374-01911\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3GM30-YEU\u003c\/td\u003e\n        \u003ctd\u003e24\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e128374-01911\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3GM30B\u003c\/td\u003e\n        \u003ctd\u003e24\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e128374-01911\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3GM30C\u003c\/td\u003e\n        \u003ctd\u003e24\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e128374-01911\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3GM30C-YEU\u003c\/td\u003e\n        \u003ctd\u003e24\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e128374-01911\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3GM30F\u003c\/td\u003e\n        \u003ctd\u003e27\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e128374-01911\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3GM30F-YEU\u003c\/td\u003e\n        \u003ctd\u003e27\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e128374-01911\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3GM30FC-YEU\u003c\/td\u003e\n        \u003ctd\u003e27\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e128374-01911\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3GM30FVE\u003c\/td\u003e\n        \u003ctd\u003e27\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e128374-01911\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e3GM30VE\u003c\/td\u003e\n        \u003ctd\u003e24\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e128374-01911\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\u003eEngine repair\/rebuild component\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\u003eHigh-temperature composite materials\u003c\/dd\u003e\n  \u003cdt\u003eDimensions\u003c\/dt\u003e\n\u003cdd\u003e28.5\" L x 14.5\" W x 0.2\" H\u003c\/dd\u003e\n  \u003cdt\u003eBore\u003c\/dt\u003e\n\u003cdd\u003e75 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 (128374-01911)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect the battery and completely drain the engine's cooling system.\u003c\/li\u003e\n  \u003cli\u003eRemove the exhaust and intake manifolds, valve cover, and any other components blocking access to the cylinder head.\u003c\/li\u003e\n  \u003cli\u003eLoosen and remove the cylinder head bolts in the reverse order of the manufacturer's specified tightening sequence.\u003c\/li\u003e\n  \u003cli\u003eCarefully lift the cylinder head off the engine block. Avoid using pry bars that could gouge the mating surfaces.\u003c\/li\u003e\n  \u003cli\u003eThoroughly clean both the cylinder head and engine block surfaces, removing all old gasket material, sealant, and residue.\u003c\/li\u003e\n  \u003cli\u003ePlace the new head gasket onto the engine block, ensuring correct orientation based on dowel pins and contours. Do not use sealant unless explicitly required by the service manual.\u003c\/li\u003e\n  \u003cli\u003eCarefully lower the cylinder head back into place.\u003c\/li\u003e\n  \u003cli\u003eLightly oil the threads of the new head bolts and install them finger-tight.\u003c\/li\u003e\n  \u003cli\u003eUsing a calibrated torque wrench, tighten the head bolts in multiple stages according to the manufacturer's torque sequence and values.\u003c\/li\u003e\n  \u003cli\u003eReinstall all previously removed components and reconnect all hoses and electrical connectors.\u003c\/li\u003e\n  \u003cli\u003eRefill the cooling system, reconnect the battery, and check for any leaks before starting the engine.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\u003csummary\u003eHow do I know if my head gasket is failing?\u003c\/summary\u003e\u003cp\u003eCommon signs include white smoke from the exhaust (burning coolant), milky or frothy engine oil (coolant contamination), persistent engine overheating, and a noticeable loss of compression or power. A chemical block test or compression test can confirm the diagnosis.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eIs this gasket compatible with the 3GM30F engine model?\u003c\/summary\u003e\u003cp\u003eYes, this cylinder head gasket is fully compatible with the Yanmar 3GM30F engine and its variants. Please refer to the compatibility table to confirm your specific model.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eDo I need to use sealant with this gasket?\u003c\/summary\u003e\u003cp\u003eNo. This is a modern composite gasket designed for dry installation. Applying sealants can interfere with its ability to seal properly and may cause premature failure. Always follow the instructions in your engine's service manual.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat are the signs of an incorrectly installed head gasket?\u003c\/summary\u003e\u003cp\u003eImmediate signs can include coolant or oil leaks from the head\/block seam, rapid overheating, or the same symptoms of head gasket failure returning shortly after repair. Improper torque or a contaminated surface are common causes.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\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\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eShipping speed \u0026amp; cost?\u003c\/summary\u003e\u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWarranty \u0026amp; returns?\u003c\/summary\u003e\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\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\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":50626125201723,"sku":"128374-01911","price":59.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/128374-01911_dce4457a-5c8c-458f-b07d-1d97e9f18ea1.jpg?v=1759816385"},{"product_id":"thermostat-cover-gasket-fits-yanmar-3jh-4jh-series-replaces-129795-49551","title":"Thermostat Cover Gasket – Fits Yanmar 3JH \u0026 4JH Series (Replaces 129795-49551)","description":"\u003csection\u003e\n\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\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis aftermarket \u003cstrong\u003eThermostat Cover Gasket – Fits Yanmar 3JH \u0026amp; 4JH Series (Replaces 129795-49551)\u003c\/strong\u003e is engineered to create a reliable seal for the thermostat housing on a wide range of Yanmar marine and industrial diesel engines. It is compatible with 3JH and 4JH series engines, including popular models like the 3JH2, 3JH5E, 4JH, and 4JH4-HTE, covering a power range from 20 to 110 HP.\u003c\/p\u003e\n\u003cp\u003eIt serves as a direct replacement for Yanmar OEM part numbers 129795-49551 and its superseded predecessor, 129470-49550.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eEnsures a direct-fit installation for proper sealing.\u003c\/li\u003e\n  \u003cli\u003eConstructed from high-temperature resistant gasket material for durability in marine diesel environments.\u003c\/li\u003e\n  \u003cli\u003eMaintains proper sealing of the thermostat housing to prevent coolant leaks.\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        \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\u003e129795-49551\u003c\/td\u003e\n        \u003ctd\u003eCurrent OEM Part Number\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYanmar\u003c\/td\u003e\n        \u003ctd\u003e129470-49550\u003c\/td\u003e\n        \u003ctd\u003eSuperseded by 129795-49551\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 part is known to fit a variety of Yanmar marine and industrial engines. Please check your specific model against the list below.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Yanmar Marine Engine 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      \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\u003e38.7\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\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\u003e38.7\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\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\u003e47.6\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH25A\u003c\/td\u003e\n\u003ctd\u003e20\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH30A\u003c\/td\u003e\n\u003ctd\u003e24\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH3E\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH4E\u003c\/td\u003e\n\u003ctd\u003e39\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH5E\u003c\/td\u003e\n\u003ctd\u003e39\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3JH40-CR\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH\u003c\/td\u003e\n\u003ctd\u003e44\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\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\u003e55\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH-HTE\u003c\/td\u003e\n\u003ctd\u003e66\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH-DTE\u003c\/td\u003e\n\u003ctd\u003e77\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH2(B)E\u003c\/td\u003e\n\u003ctd\u003e51\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH2T(B)E\u003c\/td\u003e\n\u003ctd\u003e63.2\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH2HT(B)E\u003c\/td\u003e\n\u003ctd\u003e76.1\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH2DT(B)E\u003c\/td\u003e\n\u003ctd\u003e88.4\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH2UT(B)E\u003c\/td\u003e\n\u003ctd\u003e100.6\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH3E EU\u003c\/td\u003e\n\u003ctd\u003e56\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\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\u003e75\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\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\u003e100\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\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\u003e125\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH4E\u003c\/td\u003e\n\u003ctd\u003e54\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH4AE\u003c\/td\u003e\n\u003ctd\u003e54\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH4-TE\u003c\/td\u003e\n\u003ctd\u003e75\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH4-HTE\u003c\/td\u003e\n\u003ctd\u003e110\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH5E\u003c\/td\u003e\n\u003ctd\u003e54\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH45-CR\u003c\/td\u003e\n\u003ctd\u003e45\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH57-CR\u003c\/td\u003e\n\u003ctd\u003e57\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH80-CR\u003c\/td\u003e\n\u003ctd\u003e80\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4JH110-CR\u003c\/td\u003e\n\u003ctd\u003e110\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\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\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNE84\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNE88\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3TNE88\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e3TNV88-DMP\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNE84T\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BDHQ\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BDHQ(T)\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BDSA\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BDSA(T)\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BDSAC\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BDSA2\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BDSA2T\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BDWI\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BDYE\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BNYE883\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BNYE883T\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-BPHB\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-GNP\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYanmar\u003c\/td\u003e\n\u003ctd\u003e4TNV88-XMS\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e129795-49551\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\u003eThermostat Cover Gasket\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect fit\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\u003eHigh-temperature resistant gasket material\u003c\/dd\u003e\n  \u003cdt\u003eFunction\u003c\/dt\u003e\n\u003cdd\u003eMaintains proper sealing of thermostat housing\u003c\/dd\u003e\n  \u003cdt\u003eWeight\u003c\/dt\u003e\n\u003cdd\u003e0.1 kg (0.22 lb)\u003c\/dd\u003e\n  \u003cdt\u003eDimensions\u003c\/dt\u003e\n\u003cdd\u003e10.0 cm L x 7.0 cm W x 0.1 cm 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 Thermostat Cover Gasket (129795-49551)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eEnsure the engine is completely cool and disconnect the battery.\u003c\/li\u003e\n  \u003cli\u003eDrain the engine coolant to a level below the thermostat housing.\u003c\/li\u003e\n  \u003cli\u003eCarefully remove the bolts securing the thermostat cover. Note their positions if they are different lengths.\u003c\/li\u003e\n  \u003cli\u003eRemove the old gasket and thermostat. Clean both the housing and cover surfaces meticulously, removing all old gasket material and corrosion.\u003c\/li\u003e\n  \u003cli\u003ePlace the new gasket onto the housing, ensuring it aligns with the bolt holes.\u003c\/li\u003e\n  \u003cli\u003eRe-install the thermostat cover and tighten the bolts in a crisscross pattern to the manufacturer's specified torque.\u003c\/li\u003e\n  \u003cli\u003eRefill the cooling system with the appropriate coolant.\u003c\/li\u003e\n  \u003cli\u003eReconnect the battery, start the engine, and carefully check for any leaks around the housing as the engine warms up.\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 my thermostat gasket is failing?\u003c\/summary\u003e\n  \u003cp\u003eSigns of a failing gasket include visible coolant leaks around the thermostat housing, engine overheating, or an unusually low coolant level. Look for crystallized coolant residue (typically green, pink, or orange) near the housing seam.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this gasket compatible with both raw water and freshwater cooled engines?\u003c\/summary\u003e\n  \u003cp\u003eYes, this gasket is made from high-temperature material suitable for both raw water (sea water) and freshwater\/coolant-based systems found in the compatible Yanmar engine series.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is the recommended replacement interval?\u003c\/summary\u003e\n  \u003cp\u003eIt is best practice to replace the thermostat cover gasket whenever the thermostat is replaced or the housing is removed for service. There is no fixed interval, but it should be inspected for leaks during routine engine checks.\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":50626126807355,"sku":"129795-49551","price":10.8,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/129795-49551_43d1b5d0-a1fe-4d55-92f6-cecc7f11682c.jpg?v=1759816443"}],"url":"https:\/\/seasierra.com\/collections\/yanmar-4-stroke-24hp-marine-engine-parts.oembed","provider":"SeaSierra","version":"1.0","type":"link"}