{"title":"Yamaha 4-Stroke 8-50HP Outboard Marine Engine Parts","description":"\u003csection id=\"hero\" style=\"padding:16px 0;\"\u003e\n  \u003cp\u003eDesigned for Yamaha 4‑Stroke 8–50HP outboard engines, this page helps you find compatible replacement parts and service guidance. Below you’ll find maintenance tips, commonly replaced items, and troubleshooting checks. You can also browse our main Yamaha collection at any time, and at the bottom of this page you’ll find a quick link to start browsing parts for this engine. On the collection page, use the Filter \u0026amp; Sort controls to narrow by horsepower, year range, and part category.\u003c\/p\u003e\n  \u003cp\u003e\n    \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha\" style=\"display:inline-block;padding:10px 14px;border:1px solid #0a4a8a;border-radius:6px;text-decoration:none;\"\u003eBrowse All Yamaha Parts\u003c\/a\u003e\n  \u003c\/p\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"identify-model\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eHow to Identify Your 8–50HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eLocate the serial\/nameplate on the port side of the clamp bracket (or swivel bracket). A manufactured date label is commonly nearby. Record the full model code and serial number.\u003c\/li\u003e\n    \u003cli\u003eDecode the model: “F” indicates 4‑stroke; the number indicates horsepower; suffix letters often denote shaft length (S\/L\/XL), control type (tiller vs. remote), and other options. A leading “T” (e.g., T50\/T60) typically indicates a High‑Thrust version.\u003c\/li\u003e\n    \u003cli\u003ePlatform clues: 8–9.9HP are typically compact twins; 30–40HP are commonly inline‑3; 50\/60HP share a well‑known inline‑4 EFI family. Presence of power trim\/tilt and remote controls can also indicate specific sub‑models.\u003c\/li\u003e\n    \u003cli\u003eMatch year and rigging: When ordering parts, confirm the exact model code and year to ensure correct impeller kits, anodes, plug heat range, and electrical connectors.\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\n  \u003ch3\u003ePortable 8–9.9HP\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;max-width:980px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eConfiguration\u003c\/td\u003e\n        \u003ctd\u003eTwin‑cylinder 4‑stroke, carbureted or EFI depending on year; manual or electric start; tiller or remote\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eCommon Models\u003c\/td\u003e\n        \u003ctd\u003eF8, F9.9 (short\/long shaft variants)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAdvantages\u003c\/td\u003e\n        \u003ctd\u003ePortable, fuel‑efficient, quiet operation; easy to service; great as kickers or for small craft\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eNotes\u003c\/td\u003e\n        \u003ctd\u003eConfirm propeller spline\/hub type and water pump kit by exact model code and shaft length\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003eMidrange 20–40HP\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;max-width:980px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eConfiguration\u003c\/td\u003e\n        \u003ctd\u003e4‑stroke inline‑3 EFI (common in 30\/40HP); 20–25HP may vary by year\/platform\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eCommon Models\u003c\/td\u003e\n        \u003ctd\u003eF20\/F25 (twin\/inline‑2 depending on year), F30, F40\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAdvantages\u003c\/td\u003e\n        \u003ctd\u003eLight weight with solid mid‑range torque; good fuel economy; broad prop options\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eNotes\u003c\/td\u003e\n        \u003ctd\u003eVerify gear ratio, prop pitch range, and water pump kit using the model code; check anode styles\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003e50–60HP (996cc family)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;max-width:980px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eConfiguration\u003c\/td\u003e\n        \u003ctd\u003e4‑stroke inline‑4 EFI, ~996cc; power trim \u0026amp; tilt common; compatible with Yamaha digital\/analog instrumentation\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eCommon Models\u003c\/td\u003e\n        \u003ctd\u003eF50, F60 and High‑Thrust T50\/T60 variants\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAdvantages\u003c\/td\u003e\n        \u003ctd\u003eSmooth operation, strong mid‑range, excellent fuel economy, wide prop selections\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eNotes\u003c\/td\u003e\n        \u003ctd\u003eUse correct anodes and trim‑tab anode; maintain EFI fuel filtration (10‑micron water‑separating filter recommended); follow 100‑hour oil\/gear‑oil intervals\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 general guidelines for Yamaha 4‑stroke outboards; always follow the procedure and schedule in your official owner’s\/service manual.\u003c\/p\u003e\n  \u003ctable style=\"width:100%;max-width:980px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eItem\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eInterval*\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eRemarks\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eParts Link\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eEngine oil \u0026amp; filter\u003c\/td\u003e\n        \u003ctd\u003eInitial 20 hours, then every 100 hours or annually\u003c\/td\u003e\n        \u003ctd\u003eUse FC‑W 4‑stroke marine oil of correct viscosity; replace drain gasket when needed\u003c\/td\u003e\n        \u003ctd\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-service-maintenance-kits\"\u003eYamaha Service \u0026amp; Maintenance Kits\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eGear oil (lower unit)\u003c\/td\u003e\n        \u003ctd\u003eEvery 100 hours or annually\u003c\/td\u003e\n        \u003ctd\u003eInspect for water\/milkiness and metal; replace seals if contamination is found\u003c\/td\u003e\n        \u003ctd\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-lower-unit-seal-kits\"\u003eYamaha Lower Unit Seal Kits\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSpark plugs\u003c\/td\u003e\n        \u003ctd\u003eInspect every 100 hours; replace 300 hours or as needed\u003c\/td\u003e\n        \u003ctd\u003eConfirm correct plug type\/heat range by model code and year\u003c\/td\u003e\n        \u003ctd\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\u003eFuel filters (inline\/on‑engine)\u003c\/td\u003e\n        \u003ctd\u003eInspect every 100 hours or sooner in dirty fuel environments\u003c\/td\u003e\n        \u003ctd\u003eAdd a 10‑micron water‑separating filter in the boat for EFI protection\u003c\/td\u003e\n        \u003ctd\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\u003eWater pump impeller\/kit\u003c\/td\u003e\n        \u003ctd\u003eInspect annually; replace every 2–3 seasons or 200 hours\u003c\/td\u003e\n        \u003ctd\u003eReplace sooner if weak tell‑tale or overheat alarms occur\u003c\/td\u003e\n        \u003ctd\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-water-pump-repair-kits\"\u003eYamaha Water Pump Repair Kits\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eAnodes (incl. trim‑tab anode)\u003c\/td\u003e\n        \u003ctd\u003eInspect every 100 hours; replace when 50% depleted\u003c\/td\u003e\n        \u003ctd\u003eDo not paint anodes; select correct shapes for model and bracket\u003c\/td\u003e\n        \u003ctd\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-anodes\"\u003eYamaha Anodes\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*Typical Yamaha guidance: first 20‑hour service, then 100‑hour\/annual cadence. Shorten intervals for heavy use, trolling, or harsh environments.\u003c\/p\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\/yamaha-service-maintenance-kits\"\u003eYamaha Service \u0026amp; Maintenance Kits\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eCooling System: \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-water-pump-repair-kits\"\u003eYamaha 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\u003eCorrosion Protection: \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-anodes\"\u003eYamaha Anodes\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003ePropulsion: \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-propellers\"\u003eYamaha Propellers\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eSeals \u0026amp; Gaskets: \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-gaskets\"\u003eYamaha Gaskets\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%;max-width:980px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eSymptom\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eCheck First\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;\"\u003eRelated Parts\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eWeak tell‑tale stream \/ overheat alert\u003c\/td\u003e\n        \u003ctd\u003eInspect intake screens for blockage; verify impeller condition; confirm thermostat operation; flush cooling passages after salt\/silt use\u003c\/td\u003e\n        \u003ctd\u003eWater pump kit, intake screens, thermostat, anodes\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003ePoor acceleration or power loss\u003c\/td\u003e\n        \u003ctd\u003eCheck prop damage\/pitch; verify fresh fuel; inspect on‑engine and 10‑micron filters for water\/debris; confirm plugs and throttle\/shift travel\u003c\/td\u003e\n        \u003ctd\u003ePropeller, fuel filters, spark plugs\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eHard starting \/ rough idle\u003c\/td\u003e\n        \u003ctd\u003eConfirm battery state and clean terminals; inspect plugs and plug caps; check for water in fuel; look for air leaks or kinked fuel lines\u003c\/td\u003e\n        \u003ctd\u003eSpark plugs, fuel filters, electrical connectors\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eGearcase noise or metal in gear oil\u003c\/td\u003e\n        \u003ctd\u003eDrain and inspect gear oil; look for water ingress (milky oil); check prop shaft for fishing line; pressure test if needed\u003c\/td\u003e\n        \u003ctd\u003eLower unit seal kit, gear oil, prop shaft hardware\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 between years or platforms?\u003c\/summary\u003e\n    \u003cp\u003eMany items (anodes, filters, some props) carry across years, but water pump kits, prop hubs, sensors, and electrical components can differ by model code and production year. Always confirm using the exact model code and serial number.\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\u003eInspect annually and replace every 2–3 seasons (or ~200 hours), sooner if the tell‑tale weakens, you run sandy\/silty water, or any overheat alarm occurs.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should I change lower unit gear oil?\u003c\/summary\u003e\n    \u003cp\u003eTypically every 100 hours or annually. If water or metal is present, service seals and retest before returning to service.\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 Yamaha model code, serial number, shaft length, control type (tiller or remote), and any accessories (e.g., High‑Thrust). Clear photos of the nameplate and the part location help us verify the correct components.\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 with our main Yamaha collection and refine using Filter \u0026amp; Sort to dial in your exact engine.\u003c\/p\u003e\n  \u003cp\u003e\n    \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha\" style=\"display:inline-block;padding:10px 14px;border:1px solid #0a4a8a;border-radius:6px;text-decoration:none;\"\u003eBrowse All Yamaha Parts\u003c\/a\u003e\n  \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":"thermostat-kit-fits-yamaha-f115-f130-mercury-8-50hp-replaces-6ek-12411-00-00-855676","title":"Yamaha Outboard Thermostat for F115B and F130A 4-Stroke – Replaces 6EK-12411-00, Sierra 18-3639","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;\n    word-break:normal;\n    letter-spacing:normal;\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 \u003cstrong\u003eYamaha outboard thermostat\u003c\/strong\u003e is an aftermarket replacement for select Yamaha 4-stroke outboards, including the F115B and F130A. It helps regulate engine operating temperature and is specified to begin opening at \u003cstrong\u003e122°F (50°C)\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp\u003eThe thermostat replaces Yamaha part \u003cstrong\u003e6EK-12411-00\u003c\/strong\u003e and corresponds to the full Yamaha reference \u003cstrong\u003e6EK-12411-00-00\u003c\/strong\u003e shown in supporting catalog records. It is also listed as an aftermarket equivalent to \u003cstrong\u003eSierra 18-3639\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eAftermarket replacement thermostat for Yamaha outboard cooling systems.\u003c\/li\u003e\n  \u003cli\u003eDesigned for select Yamaha F115B and F130A four-stroke applications.\u003c\/li\u003e\n  \u003cli\u003e122°F \/ 50°C opening temperature.\u003c\/li\u003e\n  \u003cli\u003eDesigned to meet the applicable OEM specification for the listed application.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eUse the references below when comparing your existing thermostat or service-manual parts list.\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\u003eReference Type\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e6EK-12411-00\u003c\/td\u003e\n        \u003ctd\u003eOEM replacement reference\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e6EK-12411-00-00\u003c\/td\u003e\n        \u003ctd\u003eFull catalog reference\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-3639\u003c\/td\u003e\n        \u003ctd\u003eAftermarket equivalent 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\u003eThis thermostat is listed for the following Yamaha four-stroke outboard applications. Always verify the complete engine model and serial number against your owner's or service manual before ordering.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Engine and Model Compatibility\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003eModel\u003c\/th\u003e\n        \u003cth\u003eRated HP\u003c\/th\u003e\n        \u003cth\u003eStroke\u003c\/th\u003e\n        \u003cth\u003eOEM Part No.\u003c\/th\u003e\n        \u003cth\u003eNotes\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eF115B\u003c\/td\u003e\n        \u003ctd\u003e115\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e6EK-12411-00\u003c\/td\u003e\n        \u003ctd\u003eConfirm the exact model and serial-number range.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eF130A\u003c\/td\u003e\n        \u003ctd\u003e130\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e6EK-12411-00\u003c\/td\u003e\n        \u003ctd\u003eConfirm the exact model and serial-number range.\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\u003eMarine outboard engine thermostat\u003c\/dd\u003e\n  \u003cdt\u003eApplication\u003c\/dt\u003e\n  \u003cdd\u003eSelect Yamaha four-stroke outboards\u003c\/dd\u003e\n  \u003cdt\u003eListed Fitment\u003c\/dt\u003e\n  \u003cdd\u003eYamaha F115B and F130A\u003c\/dd\u003e\n  \u003cdt\u003eOpening Temperature\u003c\/dt\u003e\n  \u003cdd\u003e122°F \/ 50°C\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n  \u003cdd\u003eReplacement installation using the applicable service-manual procedure\u003c\/dd\u003e\n  \u003cdt\u003eProduct Type Classification\u003c\/dt\u003e\n  \u003cdd\u003eSingle thermostat; not a thermostat-and-seal kit\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\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eImportant:\u003c\/strong\u003e Hardware, gaskets, and seals are sold separately. Confirm that the required sealing components are available before beginning installation.\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eTurn the engine off and allow it to cool completely before servicing.\u003c\/li\u003e\n  \u003cli\u003eDisconnect the battery or follow the safety procedure specified by the engine manufacturer.\u003c\/li\u003e\n  \u003cli\u003eLocate the thermostat housing and remove the cover according to the service manual.\u003c\/li\u003e\n  \u003cli\u003eRemove the old thermostat and inspect the housing, mating surfaces, and sealing components.\u003c\/li\u003e\n  \u003cli\u003eClean the mating surfaces without damaging the housing or cover.\u003c\/li\u003e\n  \u003cli\u003eInstall the replacement thermostat in the correct orientation.\u003c\/li\u003e\n  \u003cli\u003eInstall a suitable new seal or gasket if required; sealing components are not included with this thermostat.\u003c\/li\u003e\n  \u003cli\u003eReinstall the housing cover and tighten the fasteners to the manufacturer’s specified torque.\u003c\/li\u003e\n  \u003cli\u003eRun the engine according to the service-manual procedure and check for leaks or abnormal temperature warnings.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\u003csummary\u003eWhich engines is this thermostat listed for?\u003c\/summary\u003e\u003cp\u003eThe company fitment record lists Yamaha F115B and F130A four-stroke outboards. Supporting catalog records also show the corresponding thermostat reference in select F115 applications. Verify your complete model and serial number before purchase.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat is the thermostat opening temperature?\u003c\/summary\u003e\u003cp\u003eThe listed opening temperature is 122°F (50°C).\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhich part numbers does this thermostat replace?\u003c\/summary\u003e\u003cp\u003eThe primary replacement reference is Yamaha 6EK-12411-00. The full catalog format 6EK-12411-00-00 and aftermarket reference Sierra 18-3639 may also appear during parts comparison.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eIs this a complete thermostat kit?\u003c\/summary\u003e\u003cp\u003eNo. This listing is for one thermostat only. Seals, gaskets, and installation hardware are sold separately.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat are common signs of a faulty thermostat?\u003c\/summary\u003e\u003cp\u003ePossible symptoms include overheating, an engine that runs cooler than expected, slow warm-up, inconsistent temperature behavior, or an engine temperature warning. Diagnose the cooling system and follow the service manual before replacing parts.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eCan I install this thermostat myself?\u003c\/summary\u003e\u003cp\u003eInstallation may be suitable for an experienced technician or confident DIY owner, but correct orientation, sealing, and fastener torque are important. Use the service manual for your exact engine or have the work performed by a qualified marine technician.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eIs this an OEM thermostat?\u003c\/summary\u003e\u003cp\u003eThis is an aftermarket replacement, not a Yamaha-branded OEM component. It is listed as a replacement for the specified Yamaha reference and as an equivalent to Sierra 18-3639.\u003c\/p\u003e\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Information\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eVerify the complete engine model and serial number before ordering.\u003c\/li\u003e\n  \u003cli\u003eCompare the replacement part with your original thermostat and confirm the required reference number.\u003c\/li\u003e\n  \u003cli\u003eDo not operate the engine if the thermostat housing leaks or if temperature warnings continue after installation.\u003c\/li\u003e\n  \u003cli\u003eSeals, gaskets, and hardware are sold separately and may be required for installation.\u003c\/li\u003e\n  \u003cli\u003eThis product is an aftermarket replacement, not an OEM component.\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 replacement components for common outboard service applications.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplication-Focused Listings\u003c\/strong\u003e — Product references and fitment details are provided to help you compare the part with your engine.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eService-Minded Support\u003c\/strong\u003e — Always use the manufacturer’s service information for final fitment and installation requirements.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50718264295739,"sku":"23TH628","price":31.9,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/23TH628_1_8970023c-6cc7-483d-9667-750e1ba8eeab.jpg?v=1762958465"}],"url":"https:\/\/seasierra.com\/collections\/yamaha-4-stroke-8-50hp-outboard-marine-engine-parts.oembed","provider":"SeaSierra","version":"1.0","type":"link"}