{"title":"Mercury 4-Stroke 330HP Marine Engine Parts","description":"\u003csection id=\"hero\" style=\"padding:16px 0;\"\u003e\n  \u003cp style=\"max-width:860px;\"\u003e\n    This page supports Mercury 4-Stroke 330HP outboard engines and helps you find compatible parts and service information. Below you’ll find maintenance tips, common replacement parts, and troubleshooting guidance. You can also browse the main Mercury collection for a wider selection. Scroll to the bottom of the page to start browsing parts for this engine. On the collection page, use the “Filter \u0026amp; Sort” controls to narrow results by horsepower, year range, and part category\/section.\n  \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:#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 330HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eLocate the serial number plate on the outboard’s transom bracket. Record the full serial number to confirm exact parts compatibility.\u003c\/li\u003e\n    \u003cli\u003eModel codes often include shaft length (L\/XL\/XXL), rotation (standard or counter), and control type (mechanical vs. DTS). These suffixes affect gearcase seals, props, and rigging parts.\u003c\/li\u003e\n    \u003cli\u003eFor 4‑Stroke high‑horsepower engines, note whether your engine is a Verado\/SeaPro platform (V8\/V10, often DTS) versus other FourStroke configurations. Cowl badging and control system can help differentiate.\u003c\/li\u003e\n    \u003cli\u003eCapture a clear photo of the nameplate and any decals; this speeds up verification if you need assistance selecting parts.\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 \/ Platform Overview\u003c\/h2\u003e\n  \u003ch3\u003eMercury Verado V8\/V10 4‑Stroke (High Output)\u003c\/h3\u003e\n  \u003ctable style=\"max-width:940px;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;\"\u003eV8\/V10, EFI 4‑Stroke; many Verado variants are supercharged and use Digital Throttle \u0026amp; Shift (DTS).\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;\"\u003eHigh‑horsepower Verado 4‑Stroke family (V8\/V10). Exact parts are serial‑specific.\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;\"\u003eStrong torque, smooth refinement, and advanced controls; well‑suited for heavier boats and multi‑engine rigs.\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;\"\u003eCooling and gearcase parts (impeller kits, seals, anodes) can vary by midsection and gearcase option. Verify by serial number.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003eMercury SeaPro V8 4‑Stroke (Commercial Duty)\u003c\/h3\u003e\n  \u003ctable style=\"max-width:940px;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;\"\u003eV8, EFI 4‑Stroke tuned for commercial durability; often features heavy‑duty mounts and cooling components.\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;\"\u003eSeaPro high‑output V8 4‑Stroke variants. Exact service parts depend on serial number and shaft length.\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;\"\u003eBuilt for long hours and tough duty cycles; robust cooling and corrosion protection.\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 gearcases, anodes, and pump kits are SeaPro‑specific. Confirm serial and control system (mechanical vs. DTS).\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 style=\"max-width:860px;\"\u003eIntervals below are general guidelines for high‑horsepower 4‑Stroke outboards. Always follow the official service manual for your exact engine and duty cycle.\u003c\/p\u003e\n  \u003ctable style=\"max-width:100%;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 \u0026amp; oil filter\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eUse marine‑grade FC‑W oil; replace filter at each oil change.\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;\"\u003e100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eInspect magnet and fluid for metal; replace sealing washers as needed.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/mercury-lower-unit-seal-kits\"\u003eMercury Lower 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;\"\u003eUp to 300 hours or 3 years\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eShorten interval for harsh duty or fouling symptoms.\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 separator\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eReplace sooner with contaminated fuel or restricted flow.\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 years (annually in sand\/silt)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eCritical for cooling; replace sooner if tell‑tale weak or overheat alarm occurs.\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; replace when 50% depleted\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eChoose alloy for your water type (salt\/brackish\/fresh). Keep bonding clean and tight.\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 inspection\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eEach service or after strikes\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eCheck for bent blades and hub damage; verify thrust washer and nut condition.\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\n\u003c\/li\u003e\n    \u003cli\u003eGearcase Sealing — \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\u003ePropulsion — \u003ca href=\"https:\/\/seasierra.com\/collections\/propellers\"\u003ePropellers\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  \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=\"max-width:100%;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 stream or overheat alarm\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eInspect intake screens, verify hose\/tell‑tale clear, assess impeller age, and thermostat operation.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eWater pump kit, intake screen, thermostat, anodes (cooling path)\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 damage or pitch mismatch, fuel quality, and fuel filter restriction; inspect spark plugs.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003ePropeller, fuel filter, spark plugs\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;\"\u003eConfirm battery health and connections, replace plugs if fouled, check for water in fuel, inspect air\/fuel delivery.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eSpark plugs, fuel filter, injectors (service), starter circuit\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;\"\u003eVerify oil level and condition; check propshaft seals and prop hub; consider reseal if water intrusion found.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eLower unit seal kit, prop hub components\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eTrim\/tilt slow or won’t hold\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eCheck fluid level, listen for pump motor, and inspect for external leaks at rams and lines.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eTrim motor, seals\/hoses\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;\"\u003e\n  \u003ch2\u003eFAQs\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eAre parts interchangeable across years or between Verado and other FourStroke platforms?\u003c\/summary\u003e\n    \u003cp\u003eNot always. High‑horsepower Mercury 4‑Stroke platforms (Verado, SeaPro, other FourStroke V‑families) can use different cooling, gearcase, ignition, and rigging components. Always confirm by serial number and note control type (mechanical vs. DTS).\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhen should I replace the impeller on a 330HP outboard?\u003c\/summary\u003e\n    \u003cp\u003eAs a preventive measure, replace the impeller every 2–3 years (annually in sandy\/silty use) or any time you notice a weak tell‑tale stream or overheating. Heavy commercial or high‑speed use may warrant shorter intervals.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should gear oil be changed?\u003c\/summary\u003e\n    \u003cp\u003eTypically every 100 hours or annually, and immediately after any suspected impact or water intrusion. Inspect the drain plug magnet and oil for metal or milky appearance.\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 engine serial number (from the transom bracket nameplate), model designation, shaft length\/rotation, control system (mechanical or DTS), and approximate model year. Clear photos of the nameplate and the part you’re replacing are very helpful.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"cta\" style=\"padding:16px 0;\"\u003e\n  \u003cp style=\"max-width:860px;\"\u003eReady to find parts for your Mercury 4‑Stroke 330HP outboard? Browse the main Mercury collection and use the filters to narrow by horsepower, year, and part category.\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:#1e5aa6;\"\u003eShop Mercury Outboard Parts\u003c\/a\u003e\n  \u003cp style=\"margin-top:8px;color:#444;\"\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":"thermostat-repair-service-kit-fits-mercury-mercruiser-4-3l-5-0l-5-7l-7-4l-v6-v8-sterndrive-motors-replaces-807252q4-807252t4-807252t7-8m0089715","title":"Thermostat Service Kit for Mercury MerCruiser Sterndrive Engines – Replaces 807252Q4 and 807252T4","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 { padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top; }\n  table.ss-table th { white-space:nowrap; word-break:normal; letter-spacing:normal; font-weight:600; background:#f8fafc; }\n  @media (max-width:480px){ table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; } }\n\u003c\/style\u003e\n\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis \u003cstrong\u003ethermostat service kit\u003c\/strong\u003e is designed for selected Mercury MerCruiser sterndrive cooling-system applications. It provides a replacement thermostat together with the gaskets and O-ring needed to service the thermostat and housing sealing surfaces.\u003c\/p\u003e\n\u003cp\u003eThe kit replaces Mercury MerCruiser OEM part numbers \u003cstrong\u003e807252Q4\u003c\/strong\u003e and \u003cstrong\u003e807252T4\u003c\/strong\u003e. Confirm the engine model, cooling-system design, and serial-number range before ordering because thermostat and gasket requirements can vary between MerCruiser applications.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eComplete thermostat service kit for the listed application.\u003c\/li\u003e\n  \u003cli\u003eIncludes one thermostat, three thermostat-cover gaskets, one O-ring, and one thermostat-housing gasket.\u003c\/li\u003e\n  \u003cli\u003eThermostat specification: approximately \u003cstrong\u003e142°F (61°C)\u003c\/strong\u003e nominal rating.\u003c\/li\u003e\n  \u003cli\u003eIntended for the corresponding MerCruiser sterndrive cooling-system configuration; it is not a universal V6\/V8 kit.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eThese are verified replacement and aftermarket reference numbers for this kit. Reference numbers identify the intended part relationship; they do not replace an application check.\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\u003ePart Number\u003c\/th\u003e\n\u003cth\u003eRole\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury MerCruiser\u003c\/td\u003e\n\u003ctd\u003e807252Q4\u003c\/td\u003e\n\u003ctd\u003eOEM replacement reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury MerCruiser\u003c\/td\u003e\n\u003ctd\u003e807252T4\u003c\/td\u003e\n\u003ctd\u003eOEM replacement reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eSierra\u003c\/td\u003e\n\u003ctd\u003e18-3668\u003c\/td\u003e\n\u003ctd\u003eAftermarket thermostat kit reference\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\u003eCompatibility must be confirmed using the complete engine model, cooling-system arrangement, and serial number. The replacement references above are associated with selected MerCruiser sterndrive thermostat-kit applications, but a general engine-family description alone is not sufficient to confirm fitment.\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\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eApplication\u003c\/th\u003e\n\u003cth\u003eCooling System\u003c\/th\u003e\n\u003cth\u003eThermostat Rating\u003c\/th\u003e\n\u003cth\u003eFitment Check\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury MerCruiser\u003c\/td\u003e\n        \u003ctd\u003eSelected sterndrive thermostat applications using OEM references 807252Q4 or 807252T4\u003c\/td\u003e\n        \u003ctd\u003eConfirm the specific raw-water or closed-cooling configuration before installation\u003c\/td\u003e\n        \u003ctd\u003eApproximately 142°F (61°C)\u003c\/td\u003e\n        \u003ctd\u003eVerify engine model and serial number against the applicable service catalog\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 service kit\u003c\/dd\u003e\n  \u003cdt\u003eApplication\u003c\/dt\u003e\n  \u003cdd\u003eSelected Mercury MerCruiser sterndrive cooling-system applications\u003c\/dd\u003e\n  \u003cdt\u003eNominal Thermostat Rating\u003c\/dt\u003e\n  \u003cdd\u003eApproximately 142°F (61°C)\u003c\/dd\u003e\n  \u003cdt\u003eOEM Replacement References\u003c\/dt\u003e\n  \u003cdd\u003e807252Q4 and 807252T4\u003c\/dd\u003e\n  \u003cdt\u003eAftermarket Reference\u003c\/dt\u003e\n  \u003cdd\u003eSierra 18-3668\u003c\/dd\u003e\n  \u003cdt\u003eFitment Requirement\u003c\/dt\u003e\n  \u003cdd\u003eMatch engine model, cooling-system configuration, and serial number before ordering\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\u003c\/li\u003e\n  \u003cli\u003e1 x Thermostat cover gasket, reference 27-47510\u003c\/li\u003e\n  \u003cli\u003e1 x Thermostat cover gasket, reference 27-48818-1\u003c\/li\u003e\n  \u003cli\u003e1 x Thermostat cover gasket, reference 27-60208\u003c\/li\u003e\n  \u003cli\u003e1 x O-ring\u003c\/li\u003e\n  \u003cli\u003e1 x Thermostat housing gasket, reference 27-53045-1 or 27-33918\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eGasket shapes and required sealing locations depend on the corresponding housing design. Use only the gasket that matches the removed component and the service-manual installation arrangement.\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eAllow the engine to cool completely before servicing the thermostat housing.\u003c\/li\u003e\n  \u003cli\u003eClose any seacock or isolate the water supply as required by the boat and engine service procedure.\u003c\/li\u003e\n  \u003cli\u003eLocate the thermostat housing and remove the cover or housing components according to the engine service manual.\u003c\/li\u003e\n  \u003cli\u003eRecord the original thermostat orientation before removal.\u003c\/li\u003e\n  \u003cli\u003eRemove the old thermostat, O-ring, and gaskets. Do not reuse compressed or damaged sealing components.\u003c\/li\u003e\n  \u003cli\u003eClean and dry the mating surfaces without scratching the housing or cover.\u003c\/li\u003e\n  \u003cli\u003eInstall the new thermostat in the original orientation and fit the appropriate new gaskets and O-ring from the kit.\u003c\/li\u003e\n  \u003cli\u003eReassemble the housing and tighten fasteners to the engine manufacturer’s specified torque.\u003c\/li\u003e\n  \u003cli\u003eRestore the cooling-water supply and operate the engine according to the service procedure.\u003c\/li\u003e\n  \u003cli\u003eCheck for leaks and confirm that the engine reaches and maintains its normal operating temperature.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\u003csummary\u003eWhich OEM numbers does this kit replace?\u003c\/summary\u003e\u003cp\u003eThis kit is listed as a replacement for Mercury MerCruiser OEM numbers 807252Q4 and 807252T4.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat thermostat temperature rating is included?\u003c\/summary\u003e\u003cp\u003eThe associated thermostat is approximately 142°F (61°C). Do not substitute a different temperature rating unless it is specified for your exact engine application.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eDoes the kit include the thermostat and seals?\u003c\/summary\u003e\u003cp\u003eYes. The kit includes one thermostat, three thermostat-cover gaskets, one O-ring, and one thermostat-housing gasket.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eCan I use this kit on any Mercury MerCruiser V6 or V8?\u003c\/summary\u003e\u003cp\u003eNo. MerCruiser thermostat designs and gasket requirements vary by engine model, cooling-system arrangement, and serial number. Confirm all three before ordering.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eShould the old gaskets or O-ring be reused?\u003c\/summary\u003e\u003cp\u003eNo. Replace the removed sealing components with the matching new components supplied in the kit, and clean the mating surfaces before assembly.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eIs this an OEM Mercury MerCruiser part?\u003c\/summary\u003e\u003cp\u003eThis listing is for an aftermarket service kit. The OEM numbers are provided as replacement references only.\u003c\/p\u003e\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Information\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eWork only on a completely cool engine and follow the applicable marine-engine service procedure.\u003c\/li\u003e\n  \u003cli\u003eVerify the engine model, cooling-system configuration, serial number, thermostat rating, and gasket arrangement before purchase and installation.\u003c\/li\u003e\n  \u003cli\u003eDo not rely on engine displacement or cylinder count alone to confirm fitment.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended when the correct housing arrangement or cooling-system type 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 — We provide aftermarket components and service kits for common marine cooling-system repairs.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication-Focused Listings\u003c\/strong\u003e — OEM replacement references are shown to help customers compare the part with the component being replaced.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInstallation-Conscious Support\u003c\/strong\u003e — Always match the engine model, serial number, and cooling-system configuration before installation.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723787473211,"sku":"GH-TH23635-M","price":20.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/GH-TH23635-M.png?v=1763031763"}],"url":"https:\/\/seasierra.com\/collections\/mercury-4-stroke-330hp-marine-engine-parts.oembed","provider":"SeaSierra","version":"1.0","type":"link"}