{"title":"Yamaha 4-Stroke Outboard Engine 9.9-70HP Parts","description":"\u003csection id=\"hero\" style=\"padding:16px 0;\"\u003e\n  \u003cp\u003eThis page focuses on Yamaha 4-Stroke 9.9–70HP outboard engines and helps you quickly find compatible parts and service information. Below you’ll find maintenance tips, common replacement parts, and troubleshooting guidance. You can also browse the main Yamaha collection for a wider selection. Scroll to the bottom of this page to start browsing parts for this engine, and on the collection page use the Filter \u0026amp; Sort controls to narrow results by horsepower, year range, and part category\/section.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha\" style=\"display:inline-block;padding:10px 14px;background:#003366;color:#fff;text-decoration:none;border-radius:4px;\"\u003eBrowse All Yamaha Parts\u003c\/a\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"identify-model\"\u003e\n  \u003ch2\u003eHow to Identify Your 9.9–70HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eNameplate location: look for the model\/serial tag on the clamp bracket or on the swivel bracket (port or starboard).\u003c\/li\u003e\n    \u003cli\u003eReading Yamaha 4-stroke model codes: the letter “F” denotes 4‑stroke; numbers indicate horsepower (e.g., F9.9, F40, F70). Suffixes typically indicate shaft length, control type (tiller\/remote), and a production code.\u003c\/li\u003e\n    \u003cli\u003ePlatform clues: 9.9–25HP are commonly 2‑cylinder; 30–40HP are typically inline‑3; 50–70HP are inline‑4. High‑Thrust models are often marked with a leading “T” (e.g., T9.9) and use different gear ratios and propellers.\u003c\/li\u003e\n    \u003cli\u003eEFI vs. carbureted: many newer 4‑strokes use EFI; earlier models may be carbureted. Match parts using the exact model code and serial.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"engine-overview\"\u003e\n  \u003ch2\u003ePlatform Overview\u003c\/h2\u003e\n\n  \u003ch3\u003eSmall Twin-Cylinder (F9.9–F25, including T9.9 High-Thrust)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;max-width:900px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eInline‑2 SOHC 4‑stroke; carbureted on earlier units, EFI on newer models.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eCommon Models\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eF9.9, T9.9 (High‑Thrust), F15, F20, F25\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eAdvantages\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eLightweight, portable, excellent trolling manners and fuel economy.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eNotes\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eT‑series High‑Thrust models use different props and reduction ratios; verify prop, exhaust housing, and gearcase parts by model code.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003eMid Inline‑3 (F30–F40)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;max-width:900px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eInline‑3 4‑stroke with EFI on most later models; compact block with broad mid‑range torque.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eCommon Models\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eF30, F40\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eAdvantages\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eStrong mid‑range, smooth operation, good fuel economy.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eNotes\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eMany service parts (filters, anodes) are platform‑common, but always confirm by full model code and serial.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003eInline‑4 (F50–F70)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;max-width:900px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eFeature\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eDescription\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eInline‑4 EFI 4‑stroke; lightweight designs with SOHC valvetrain.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eCommon Models\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eF50, F60, F70\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eAdvantages\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eVery smooth, quiet, and efficient; strong top‑end for hulls in this class.\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eNotes\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eF70 has unique intake\/exhaust and some gearcase differences; verify gaskets, sensors, and prop hardware by model.\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\"\u003e\n  \u003ch2\u003eRoutine Maintenance \u0026amp; Service Parts\u003c\/h2\u003e\n  \u003cp\u003eIntervals below are general guidelines for Yamaha 4‑stroke outboards in the 9.9–70HP range. Always follow the service schedule and specifications in your official Yamaha manual.\u003c\/p\u003e\n  \u003ctable style=\"width:100%;max-width:1000px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eItem\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eInterval*\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eRemarks\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eParts Link\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eEngine oil + filter\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003e100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eUse NMMA FC‑W oil; replace the oil filter at each oil change.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\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 style=\"padding:6px 0;\"\u003eGear oil (lower unit)\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003e100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eInspect for water intrusion (milky oil). Replace seals if contamination is found.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\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 style=\"padding:6px 0;\"\u003eSpark plugs\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003e100 hrs or 1–2 seasons\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eReplace sooner if fouled from excessive idling or stale fuel.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\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:6px 0;\"\u003eFuel filter \/ water separator\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003e100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eDrain\/replace if water or debris is present; keep fresh fuel on board.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\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:6px 0;\"\u003eWater pump impeller\/kit\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003e2–3 seasons (inspect annually)\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eReplace more frequently in sandy\/silty water or if tell‑tale weakens.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\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 style=\"padding:6px 0;\"\u003eAnodes (sacrificial)\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eInspect every 50 hrs; replace as needed\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eUse the correct alloy for your waters (salt\/brackish\/fresh).\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\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*Intervals may vary by model and duty cycle. Always confirm with your Yamaha service manual.\u003c\/p\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"common-parts\"\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 — \u003ca href=\"https:\/\/seasierra.com\/collections\/spark-plug\"\u003eSpark Plugs\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003ePropellers \u0026amp; Hardware — \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-propellers\"\u003eYamaha Propellers\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\u003eGearcase Service — \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-lower-unit-seal-kits\"\u003eYamaha Lower Unit Seal Kits\u003c\/a\u003e\n\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"troubleshooting\"\u003e\n  \u003ch2\u003eCommon Symptoms \u0026amp; Quick Checks\u003c\/h2\u003e\n  \u003ctable style=\"width:100%;max-width:1000px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eSymptom\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eCheck First\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ccc;\"\u003eRelated Parts\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eWeak tell‑tale or overheat alarm\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eInspect intake screen for blockage; verify impeller condition and thermostat operation.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eWater pump kit, thermostat, intake screen\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eHard starting or rough idle\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eConfirm fresh fuel; check spark plugs; inspect\/replace fuel filter; for carb models, clean jets; for EFI, check low‑pressure filter.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eSpark plugs, fuel filter, carburetor components\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003ePoor acceleration or power loss\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eCheck prop for dings and correct pitch; verify compression; inspect air\/fuel filters and throttle linkage.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003ePropeller, fuel filter, air intake components\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eGearcase noise or milky gear oil\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eDrain and inspect gear oil; check prop‑shaft seal and driveshaft seal; look for fishing line in seals.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eLower unit seal kit, bearings, gear oil\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eExcessive exhaust smoke on 4‑stroke\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eVerify oil level (overfilled can cause smoking); ensure proper warm‑up; check PCV\/breather.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eOil, PCV\/breather components, spark plugs\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"faq\"\u003e\n  \u003ch2\u003eFAQs\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eAre parts interchangeable between years or platforms?\u003c\/summary\u003e\n    \u003cp\u003eSome filters, anodes, and hardware cross over within a platform (e.g., F50–F60). However, changes in induction, sensors, and gearcases mean many items are model‑specific. Always confirm using the full Yamaha model code and serial.\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 sooner if the tell‑tale weakens, the engine overheats, or you run in sandy\/silty water.\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 found in the oil, service seals and recheck after a short run.\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 complete model code (e.g., F70...), serial number, shaft length, control type (tiller\/remote), and whether it is a High‑Thrust model.\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? Browse our Yamaha collection and refine results with Filter \u0026amp; Sort.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha\" style=\"display:inline-block;padding:10px 14px;background:#003366;color:#fff;text-decoration:none;border-radius:4px;\"\u003eBrowse All Yamaha Parts\u003c\/a\u003e\n  \u003cp style=\"margin-top:8px;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-fits-yamaha-9-9-70-hp-4-stroke-outboards-replaces-6g8-12411-00-69m-12411-00","title":"60°C Thermostat for Yamaha F6A, F8B, F8C, FT8D, F9.9A, F9.9B, F9.9F, F9.9J, FT9.9G and FT9.9L Outboards","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 aftermarket \u003cstrong\u003e60°C outboard thermostat\u003c\/strong\u003e is designed for the specified Yamaha four-stroke models. It helps regulate engine operating temperature and is supplied as a single thermostat for replacement of the original component.\u003c\/p\u003e\n\u003cp\u003eThe thermostat is listed as aftermarket reference \u003cstrong\u003e18-3541\u003c\/strong\u003e. Its primary Yamaha reference is \u003cstrong\u003e66M-12411-01\u003c\/strong\u003e, which supersedes Yamaha references \u003cstrong\u003e6G8-12411-00\u003c\/strong\u003e, \u003cstrong\u003e6G8-12411-01\u003c\/strong\u003e, \u003cstrong\u003e6G8-12411-02\u003c\/strong\u003e and \u003cstrong\u003e6G8-12411-03\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eSingle replacement thermostat\u003c\/li\u003e\n  \u003cli\u003eOpening temperature: 60°C\u003c\/li\u003e\n  \u003cli\u003eFor the Yamaha four-stroke models listed below\u003c\/li\u003e\n  \u003cli\u003eAftermarket replacement; not a Yamaha-branded OEM component\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number References\u003c\/h2\u003e\n\u003cp\u003eUse the following references when comparing your original thermostat. Confirm the complete engine model before ordering.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number References\"\u003e\n    \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eReference\u003c\/th\u003e\n\u003cth\u003eDescription\u003c\/th\u003e\n\u003cth\u003eRelationship\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eAftermarket\u003c\/td\u003e\n\u003ctd\u003e18-3541\u003c\/td\u003e\n\u003ctd\u003eThermostat\u003c\/td\u003e\n\u003ctd\u003eAftermarket reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003e66M-12411-01\u003c\/td\u003e\n\u003ctd\u003eThermostat\u003c\/td\u003e\n\u003ctd\u003ePrimary Yamaha reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003e6G8-12411-00\u003c\/td\u003e\n\u003ctd\u003eThermostat\u003c\/td\u003e\n\u003ctd\u003eSuperseded reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003e6G8-12411-01\u003c\/td\u003e\n\u003ctd\u003eThermostat\u003c\/td\u003e\n\u003ctd\u003eSuperseded reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003e6G8-12411-02\u003c\/td\u003e\n\u003ctd\u003eThermostat\u003c\/td\u003e\n\u003ctd\u003eSuperseded reference\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003e6G8-12411-03\u003c\/td\u003e\n\u003ctd\u003eThermostat\u003c\/td\u003e\n\u003ctd\u003eSuperseded 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\u003eThe company fitment record specifies the following Yamaha four-stroke models. Model suffixes, year ranges and serial-number conditions can affect fitment, so compare your complete model designation with the information below and verify against the original thermostat or service documentation.\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\u003eModel\u003c\/th\u003e\n\u003cth\u003eStroke\u003c\/th\u003e\n\u003cth\u003eThermostat Temperature\u003c\/th\u003e\n\u003cth\u003eReference\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003eF6A\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e60°C\u003c\/td\u003e\n\u003ctd\u003e66M-12411-01\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003eF8B\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e60°C\u003c\/td\u003e\n\u003ctd\u003e66M-12411-01\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003eF8C\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e60°C\u003c\/td\u003e\n\u003ctd\u003e66M-12411-01\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003eFT8D\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e60°C\u003c\/td\u003e\n\u003ctd\u003e66M-12411-01\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003eF9.9A, F9.9B, F9.9F, F9.9J\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e60°C\u003c\/td\u003e\n\u003ctd\u003e66M-12411-01\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003eFT9.9A, FT9.9G, FT9.9L\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e60°C\u003c\/td\u003e\n\u003ctd\u003e66M-12411-01\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 thermostat\u003c\/dd\u003e\n  \u003cdt\u003eQuantity\u003c\/dt\u003e\n  \u003cdd\u003e1 thermostat\u003c\/dd\u003e\n  \u003cdt\u003eOpening Temperature\u003c\/dt\u003e\n  \u003cdd\u003e60°C\u003c\/dd\u003e\n  \u003cdt\u003eApplication\u003c\/dt\u003e\n  \u003cdd\u003eSpecified Yamaha four-stroke outboard models\u003c\/dd\u003e\n  \u003cdt\u003eAftermarket Reference\u003c\/dt\u003e\n  \u003cdd\u003e18-3541\u003c\/dd\u003e\n  \u003cdt\u003ePrimary Yamaha Reference\u003c\/dt\u003e\n  \u003cdd\u003e66M-12411-01\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e1 × 60°C aftermarket thermostat\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eA gasket is not listed as an included component for this product. If your installation requires a replacement thermostat gasket, confirm the correct gasket separately for your exact engine model.\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eAllow the engine to cool completely before starting work.\u003c\/li\u003e\n  \u003cli\u003eDisconnect the battery if required by your service procedure and keep the work area clean.\u003c\/li\u003e\n  \u003cli\u003eLocate the thermostat housing and remove the cover according to the engine service manual.\u003c\/li\u003e\n  \u003cli\u003eRemove the old thermostat and inspect the housing, sealing surfaces and related gasket.\u003c\/li\u003e\n  \u003cli\u003eClean the mating surfaces without damaging the housing.\u003c\/li\u003e\n  \u003cli\u003eInstall the replacement thermostat in the correct orientation for your specific Yamaha engine.\u003c\/li\u003e\n  \u003cli\u003eUse the correct new gasket if the original gasket is damaged or the service manual requires replacement. A gasket is not included with this thermostat.\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 according to the service procedure and check for leaks and correct 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 does this thermostat open at?\u003c\/summary\u003e\n  \u003cp\u003eThis thermostat is specified with a 60°C opening temperature.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this a complete thermostat kit?\u003c\/summary\u003e\n  \u003cp\u003eNo. This listing is for one thermostat only. A gasket or O-ring is not listed as included.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhich Yamaha references does it replace?\u003c\/summary\u003e\n  \u003cp\u003eThe company reference lists Yamaha 66M-12411-01 as the primary reference and identifies 6G8-12411-00, 6G8-12411-01, 6G8-12411-02 and 6G8-12411-03 as superseded references.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWill it fit every Yamaha four-stroke outboard?\u003c\/summary\u003e\n  \u003cp\u003eNo. Fitment is limited to the specified models: F6A, F8B, F8C, FT8D, F9.9A, FT9.9A, F9.9B, F9.9F, F9.9J, FT9.9G and FT9.9L. Verify the complete model designation and original part before ordering.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this an OEM Yamaha thermostat?\u003c\/summary\u003e\n  \u003cp\u003eNo. This is an aftermarket replacement referenced against the listed Yamaha part numbers.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Information\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eWork only on a cool engine and follow the applicable service manual.\u003c\/li\u003e\n  \u003cli\u003eConfirm the complete model designation, stroke and original thermostat reference before purchase.\u003c\/li\u003e\n  \u003cli\u003eDo not rely on horsepower range alone to determine fitment.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended if you are unfamiliar with outboard cooling-system service.\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 aftermarket components for routine outboard maintenance and repair.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFitment-Focused Listings\u003c\/strong\u003e — Product references and specified applications are provided to help you compare the replacement with your original part.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInstallation Awareness\u003c\/strong\u003e — Always use the correct service procedure and replace related seals or gaskets when required by the engine manufacturer.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723987816763,"sku":"24TH501","price":23.1,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/Thermostat_for_Yamaha_4_Stroke_F_99_to_70_HP_Outboard_Motor_6G8-12411-00____6G8-12411-00_-_JLM_MARINE-8291296.jpg?v=1763039544"}],"url":"https:\/\/seasierra.com\/collections\/yamaha-4-stroke-outboard-engine-9-9-70hp-parts.oembed","provider":"SeaSierra","version":"1.0","type":"link"}