{"title":"Mercury 4-Stroke 3-6HP Outboard Marine Engine Parts","description":"\u003csection id=\"hero\" style=\"padding:16px 0;\"\u003e\n  \u003cp\u003eDesigned for Mercury 4-Stroke 3–6HP outboard engines, this page helps you find compatible parts and practical service information. You’ll find maintenance tips, common replacement parts, and troubleshooting guidance below. You can also browse our main Mercury collection, and when you get to the collection page use the Filter \u0026amp; Sort controls to narrow by horsepower, year range, and part category\/section. Scroll to the bottom of this page to start browsing parts for this engine.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\" style=\"display:inline-block;padding:10px 16px;border:1px solid #1e5aa6;border-radius:6px;text-decoration:none;color:#fff;background:#1e5aa6;\"\u003eBrowse All Mercury Parts\u003c\/a\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"identify-model\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eHow to Identify Your 3–6HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eLocate the nameplate\/serial tag on the transom clamp bracket or swivel bracket. The serial number is the best way to confirm parts.\u003c\/li\u003e\n    \u003cli\u003eRead the model code and suffix: these indicate horsepower, shaft length (short\/long), starting method (manual\/electric if equipped), and regional variations.\u003c\/li\u003e\n    \u003cli\u003eVerify it’s a 4‑Stroke: look for the crankcase oil fill\/dipstick and valve cover; 4‑stroke models do not require premix fuel.\u003c\/li\u003e\n    \u003cli\u003e3–6HP families often share many service items; verify compatibility by serial number and configuration before ordering.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"engine-overview\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eEngine Overview\u003c\/h2\u003e\n  \u003ch3\u003ePortable 4‑Stroke (3–6HP)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;border-collapse:collapse;max-width:900px;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;padding:8px;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;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;\"\u003eSingle‑cylinder OHV 4‑stroke, carbureted; portable tiller steer; manual start (with optional charging coil on some models).\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 include 3.5 HP 4‑Stroke Carburetor, 4 HP 4‑Stroke, 5 HP 4‑Stroke, and 6 HP 4‑Stroke variants.\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;\"\u003eLightweight and fuel‑efficient with quiet operation; straightforward maintenance; ideal for tenders, small inflatables, and dinghies.\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;\"\u003eMany wear parts (impeller, anodes, some gearcase seals, and props) are shared across 3–6HP families, but jets, ignition, and charge options may differ by serial range and region—confirm by 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=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eRoutine Maintenance \u0026amp; Service Parts\u003c\/h2\u003e\n  \u003cp\u003eIntervals below are common guidelines for small 4‑stroke outboards. Always follow your official service manual and local operating conditions.\u003c\/p\u003e\n  \u003ctable style=\"width:100%;border-collapse:collapse;max-width:900px;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;padding:8px;\"\u003eItem\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;padding:8px;\"\u003eInterval*\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;padding:8px;\"\u003eRemarks\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;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 (and filter if equipped)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eFirst 20 hours, then every 100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eUse FC‑W 4‑stroke outboard oil; many 3–6HP models do not use a replaceable filter—confirm by serial\/model.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/oil-filters\"\u003eOil 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 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eInspect for water\/milkiness and metal; replace drain plug gaskets; pressure test if contamination is found.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\"\u003eMercury Outboard Parts\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 hours; replace as needed or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eCheck gap and insulator color; replace if fouled, worn, or corroded.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\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 #eee;\"\u003eFuel filter \/ inline filter\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eEvery 100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eReplace sooner if debris or stale fuel is suspected; keep water out of fuel system.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/fuel-filters-1\"\u003eFuel 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 2–3 seasons (or 200 hours) and anytime overheat occurs\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eCritical for cooling on shallow\/sandy launches; replace more often in silty water.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-water-pump-repair-kits\"\u003eMercury Water Pump Repair 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 (zinc\/aluminum\/magnesium)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eInspect every 50 hours or each haul‑out; 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); ensure good electrical contact.\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      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003ePropeller and hardware check\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eInspect each trip; remove and grease splines seasonally\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eRemove debris\/fishing line; inspect cotter pin\/prop nut; verify pitch for load.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/propellers\"\u003ePropellers\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"common-parts\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eFrequently Used Parts Categories\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eRoutine Service: \u003ca href=\"https:\/\/seasierra.com\/collections\/service-maintenance-kits\"\u003eService \u0026amp; Maintenance Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eCooling System: \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-water-pump-repair-kits\"\u003eMercury Water Pump Repair Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eFuel System: \u003ca href=\"https:\/\/seasierra.com\/collections\/fuel-filters-1\"\u003eFuel Filters\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\/spark-plug\"\u003eSpark Plugs\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\u003eGearcase Seals: \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-lower-unit-seal-kits\"\u003eMercury Lower Unit Seal Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003ePropellers \u0026amp; Hardware: \u003ca href=\"https:\/\/seasierra.com\/collections\/propellers\"\u003ePropellers\u003c\/a\u003e\n\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"troubleshooting\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eCommon Symptoms \u0026amp; Quick Checks\u003c\/h2\u003e\n  \u003ctable style=\"width:100%;border-collapse:collapse;max-width:900px;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;padding:8px;\"\u003eSymptom\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;padding:8px;\"\u003eCheck First\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;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 stream or overheat alarm\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eClear the tell‑tale, inspect intake screen for debris, verify pump impeller condition, and check thermostat operation.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eWater pump kit, intake screen, thermostat, \u003ca href=\"https:\/\/seasierra.com\/collections\/anodes\"\u003eanodes\u003c\/a\u003e\n\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;\"\u003eUse fresh fuel; prime system; verify choke\/enrichment and idle speed; inspect spark plug condition and gap.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e\n\u003ca href=\"https:\/\/seasierra.com\/collections\/fuel-filters-1\"\u003efuel filter\u003c\/a\u003e, \u003ca href=\"https:\/\/seasierra.com\/collections\/carburetor\"\u003ecarburetor\u003c\/a\u003e components, \u003ca href=\"https:\/\/seasierra.com\/collections\/spark-plug\"\u003espark plug\u003c\/a\u003e\n\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\/incorrect pitch, verify throttle opening, confirm venting on fuel tank, and inspect for water in fuel.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e\n\u003ca href=\"https:\/\/seasierra.com\/collections\/propellers\"\u003epropeller\u003c\/a\u003e, \u003ca href=\"https:\/\/seasierra.com\/collections\/fuel-filters-1\"\u003efuel filter\u003c\/a\u003e, \u003ca href=\"https:\/\/seasierra.com\/collections\/spark-plug\"\u003espark plug\u003c\/a\u003e\n\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 and inspect gear oil; look for water intrusion; check prop shaft seal and drain\/fill plug gaskets; pressure test if needed.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e\n\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-lower-unit-seal-kits\"\u003elower unit seal kit\u003c\/a\u003e, \u003ca href=\"https:\/\/seasierra.com\/collections\/bearings\"\u003ebearings\u003c\/a\u003e\n\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=\"padding:16px 0;max-width:900px;\"\u003e\n  \u003ch2\u003eFAQs\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eAre parts interchangeable between 3.5, 4, 5, and 6HP models?\u003c\/summary\u003e\n    \u003cp\u003eMany wear items cross over within the 3–6HP 4‑stroke family, but differences in carburetor jetting, ignition, shaft length, and charging options exist. Always confirm using your serial number and model code.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhen should I replace the water pump impeller?\u003c\/summary\u003e\n    \u003cp\u003eReplace the impeller every 2–3 seasons (or about 200 hours), and immediately after any overheat or if the tell‑tale stream weakens. Sandy or silty water may require more frequent service.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should I change the lower unit gear oil?\u003c\/summary\u003e\n    \u003cp\u003eChange gear oil every 100 hours or annually, and anytime contamination (water\/milkiness or metal) is found. Replace drain\/fill plug gaskets and pressure test the gearcase if leaks are suspected.\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 engine serial number, model code, horsepower, shaft length, starting method, and a description or photo of the part. This ensures you receive parts that match your exact configuration.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"cta\" style=\"padding:16px 0;\"\u003e\n  \u003cp\u003eReady to find parts by horsepower, year, and model? Start in our main Mercury collection and refine with Filter \u0026amp; Sort to dial in exactly what you need.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-outboard-parts\" style=\"display:inline-block;padding:10px 16px;border:1px solid #1e5aa6;border-radius:6px;text-decoration:none;color:#fff;background:#1e5aa6;\"\u003eShop Mercury Outboard Parts\u003c\/a\u003e\n  \u003cp style=\"margin-top:8px;color:#555;\"\u003eIf you’re unsure about your model, send us a clear 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":"thermostat-fits-tohatsu-mercury-evinrude-2-6-hp-4-stroke-replaces-3h6-01030-0-804540","title":"Outboard Thermostat for Mercury\/Mariner, Tohatsu\/Nissan \u0026 Evinrude\/Johnson – 50°C (122°F)","description":"\u003csection\u003e\n\u003cstyle\u003e\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\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  table.ss-table th {\n    white-space:nowrap;\n    word-break:normal;\n    letter-spacing:normal;\n    font-weight:600;\n    background:#f8fafc;\n  }\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 outboard thermostat is designed for selected Mercury\/Mariner, Tohatsu\/Nissan, and Evinrude\/Johnson marine engines. It helps regulate engine temperature at the specified \u003cstrong\u003e50°C (122°F)\u003c\/strong\u003e operating point for the compatible applications listed below.\u003c\/p\u003e\n\u003cp\u003eThe thermostat is sold as a \u003cstrong\u003esingle replacement component\u003c\/strong\u003e. It is listed for applications using Mercury references \u003cstrong\u003e804540\u003c\/strong\u003e and \u003cstrong\u003e853704\u003c\/strong\u003e, Tohatsu references \u003cstrong\u003e3H6-01030-0\u003c\/strong\u003e and \u003cstrong\u003e345-01030-0\u003c\/strong\u003e, Evinrude\/Johnson reference \u003cstrong\u003e5040958\u003c\/strong\u003e, and Sierra reference \u003cstrong\u003e18-3638\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eReplacement thermostat for selected outboard cooling systems.\u003c\/li\u003e\n  \u003cli\u003eTemperature specification: 50°C (122°F).\u003c\/li\u003e\n  \u003cli\u003eOne thermostat included.\u003c\/li\u003e\n  \u003cli\u003eConfirm the complete engine model, horsepower, stroke, and serial-number range before ordering.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eThe following manufacturer and aftermarket references are listed for identification and cross-reference purposes. Always compare the original part and engine application before installation.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n    \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eReference\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e804540\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e853704\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTohatsu\/Nissan\u003c\/td\u003e\n\u003ctd\u003e3H6-01030-0\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTohatsu\/Nissan\u003c\/td\u003e\n\u003ctd\u003e345-01030-0\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTohatsu\/Nissan\u003c\/td\u003e\n\u003ctd\u003e3H6010300 \/ 3H6010300M\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eEvinrude\/Johnson\u003c\/td\u003e\n\u003ctd\u003e5040958\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSierra\u003c\/td\u003e\n\u003ctd\u003e18-3638\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eEngine Compatibility\u003c\/h2\u003e\n\u003cp\u003eCompany fitment information identifies the following application groups. Model, stroke, and serial-number conditions must remain together when checking compatibility; horsepower alone is not sufficient.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Mercury and Mariner Compatibility\"\u003e\n    \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eApplication\u003c\/th\u003e\n\u003cth\u003eHorsepower\u003c\/th\u003e\n\u003cth\u003eStroke \/ Configuration\u003c\/th\u003e\n\u003cth\u003eSerial Condition\u003c\/th\u003e\n\u003cth\u003eReference\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n\u003ctd\u003eSelected carbureted models\u003c\/td\u003e\n\u003ctd\u003e2.5–3.5 HP\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e0R131842 and up\u003c\/td\u003e\n\u003ctd\u003e804540\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n\u003ctd\u003eSelected models\u003c\/td\u003e\n\u003ctd\u003e4–6 HP\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e0R411838 and up\u003c\/td\u003e\n\u003ctd\u003e804540\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\/Mariner International\u003c\/td\u003e\n\u003ctd\u003eTwo-cylinder, 430 cc applications\u003c\/td\u003e\n\u003ctd\u003e25–30 HP\u003c\/td\u003e\n\u003ctd\u003eConfirm the engine model and stroke\u003c\/td\u003e\n\u003ctd\u003eConfirm the engine serial number\u003c\/td\u003e\n\u003ctd\u003e804540 \/ 853704\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Tohatsu and Nissan Compatibility\"\u003e\n    \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eApplication Range\u003c\/th\u003e\n\u003cth\u003eHorsepower\u003c\/th\u003e\n\u003cth\u003eReference\u003c\/th\u003e\n\u003cth\u003eNotes\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eTohatsu\/Nissan\u003c\/td\u003e\n\u003ctd\u003eSelected marine outboard applications\u003c\/td\u003e\n\u003ctd\u003e3.5–40 HP\u003c\/td\u003e\n\u003ctd\u003e3H6-01030-0 \/ 345-01030-0\u003c\/td\u003e\n\u003ctd\u003eVerify the exact model and serial number.\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Evinrude and Johnson Compatibility\"\u003e\n    \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eApplication\u003c\/th\u003e\n\u003cth\u003eHorsepower\u003c\/th\u003e\n\u003cth\u003eReference\u003c\/th\u003e\n\u003cth\u003eNotes\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eEvinrude\/Johnson\u003c\/td\u003e\n\u003ctd\u003eSelected outboard applications\u003c\/td\u003e\n\u003ctd\u003e3, 4, and 6 HP\u003c\/td\u003e\n\u003ctd\u003e5040958\u003c\/td\u003e\n\u003ctd\u003eVerify the exact model, year, and serial number.\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eProduct Type\u003c\/dt\u003e\n  \u003cdd\u003eOutboard engine thermostat\u003c\/dd\u003e\n  \u003cdt\u003eTemperature Specification\u003c\/dt\u003e\n  \u003cdd\u003e50°C (122°F)\u003c\/dd\u003e\n  \u003cdt\u003eInstallation Location\u003c\/dt\u003e\n  \u003cdd\u003eEngine cooling system \/ thermostat housing\u003c\/dd\u003e\n  \u003cdt\u003eProduct Format\u003c\/dt\u003e\n  \u003cdd\u003eSingle replacement component\u003c\/dd\u003e\n  \u003cdt\u003eReplacement References\u003c\/dt\u003e\n  \u003cdd\u003eMercury 804540 and 853704; Tohatsu\/Nissan 3H6-01030-0 and 345-01030-0; Evinrude\/Johnson 5040958; Sierra 18-3638\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 Outboard thermostat\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eA gasket, seal, or additional installation hardware is not specified as included. Reuse only components that are confirmed serviceable, or obtain replacement sealing parts separately when required by the engine service procedure.\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eAllow the engine to cool completely before beginning work.\u003c\/li\u003e\n  \u003cli\u003ePrevent accidental starting and follow the safety instructions in the engine service manual.\u003c\/li\u003e\n  \u003cli\u003eLocate the thermostat housing and confirm that the replacement part matches the original component.\u003c\/li\u003e\n  \u003cli\u003eRemove the housing cover according to the manufacturer's procedure.\u003c\/li\u003e\n  \u003cli\u003eRemove the old thermostat and inspect the housing, sealing surfaces, and related components for damage or deposits.\u003c\/li\u003e\n  \u003cli\u003eInstall the replacement thermostat in the same orientation as the original part.\u003c\/li\u003e\n  \u003cli\u003eInstall a suitable new gasket or seal if required by the engine service manual. No gasket is specified as included with this product.\u003c\/li\u003e\n  \u003cli\u003eReinstall the housing cover and tighten fasteners to the manufacturer's specified torque.\u003c\/li\u003e\n  \u003cli\u003eRun the engine using the correct test procedure and check for leaks and proper cooling-system operation.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat temperature is this thermostat specified for?\u003c\/summary\u003e\n  \u003cp\u003eThe company specification is \u003cstrong\u003e50°C (122°F)\u003c\/strong\u003e. This is the listed temperature specification for the compatible applications.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I confirm that it fits my engine?\u003c\/summary\u003e\n  \u003cp\u003eCompare your original thermostat reference with the Part Number Matrix, then verify the engine brand, exact model, horsepower, stroke or configuration, year where applicable, and serial-number range. For Mercury\/Mariner applications, the listed serial conditions include 0R131842 and up for selected 2.5–3.5 HP 4-stroke models and 0R411838 and up for selected 4–6 HP 4-stroke models.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eDoes this listing include a gasket or housing?\u003c\/summary\u003e\n  \u003cp\u003eNo. The package contains one thermostat only. A gasket, seal, housing, or other installation hardware is not specified as included.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are common symptoms of a thermostat problem?\u003c\/summary\u003e\n  \u003cp\u003ePossible symptoms include overheating, abnormal operating temperature, or an engine that runs cooler than expected. Cooling-system problems can have several causes, so inspect water flow, passages, seals, and related components before replacing the thermostat.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this an OEM part?\u003c\/summary\u003e\n  \u003cp\u003eThis is an aftermarket replacement component. The manufacturer references shown above are provided for identification and compatibility cross-reference only; this product is not represented as a genuine OEM component.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Information\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eDo not rely on horsepower alone to determine fitment.\u003c\/li\u003e\n  \u003cli\u003eVerify the exact engine model, stroke or configuration, year where applicable, and serial number before ordering.\u003c\/li\u003e\n  \u003cli\u003eCompare the replacement part with the original thermostat and inspect all sealing surfaces before installation.\u003c\/li\u003e\n  \u003cli\u003eUse the engine manufacturer's service procedure and specified torque values.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended when the correct procedure or application is uncertain.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMarine Replacement Parts\u003c\/strong\u003e — Practical replacement components for selected marine engine applications.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication-Focused Listings\u003c\/strong\u003e — Reference numbers and fitment conditions are provided to support accurate part selection.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSupport for Maintenance Work\u003c\/strong\u003e — Confirm your engine details and original part before ordering or installing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723807920443,"sku":"23TH619","price":31.9,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/Thermostat_for_Tohatsu_Mercury_2-6_hp_4-St_3H6-01030-0_804540___345-01030-0_3H6-01030-0_-_JLM_MARINE-8291185.jpg?v=1763032298"}],"url":"https:\/\/seasierra.com\/collections\/mercury-4-stroke-3-6hp-outboard-marine-engine-parts.oembed","provider":"SeaSierra","version":"1.0","type":"link"}