{"title":"Yamaha 4-Stroke 8-25HP Outboard Engine Parts","description":"\u003csection id=\"hero\" style=\"padding:16px 0;\"\u003e\n  \u003cp\u003eThis page covers Yamaha 4-Stroke 8–25HP 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 any time. Scroll down to the bottom of the page to start browsing parts for this engine, and remember you can use the “Filter \u0026amp; Sort” controls on the collection page to narrow results by horsepower, year range, and part category.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha\" style=\"display:inline-block;margin-top:8px;padding:10px 14px;background:#0a4a7a;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\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003eHow to Identify Your 8–25HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eLocate the nameplate\/serial sticker on the transom bracket (starboard side) or swivel bracket. It shows the model code, serial number, and shaft length.\u003c\/li\u003e\n    \u003cli\u003eRead the model code: for example “F15ELH” — “F” = 4‑stroke, numbers = horsepower, “S\/L\/X” = shaft length, letters often indicate start\/control type (e.g., electric start, tiller\/remote), and generation\/year suffix.\u003c\/li\u003e\n    \u003cli\u003ePlatform clues: 8–15HP models are typically twin‑cylinder carbureted four‑strokes on earlier years; 20–25HP moved from carburetor to EFI on newer generations. FT models designate High Thrust variants with different gear ratios and props.\u003c\/li\u003e\n    \u003cli\u003eConfirm propeller hub style (spline vs. pin drive on some older small HP models) before ordering propellers or hardware.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"engine-overview\" style=\"padding:16px 0;\"\u003e\n  \u003ch2\u003ePlatform Overview\u003c\/h2\u003e\n  \u003ch3\u003eSmall Twin (F8\/F9.9\/F13.5\/F15)\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 #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;\"\u003eTwin‑cylinder 4‑stroke, typically carbureted on earlier years.\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;\"\u003eF8, F9.9, F13.5, F15 (various shaft lengths and start\/control options).\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 efficient; easy dockside manners; widely available tune‑up parts.\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 ignition, fuel, and cooling parts interchange across close HP variants; verify by model code for prop hub style and gear ratio.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003eMid Twin \u0026amp; High Thrust (F20\/F25\/FT20\/FT25)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;max-width:900px;border-collapse:collapse;margin-top:12px;\"\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;\"\u003eTwin‑cylinder 4‑stroke; earlier units carbureted, later generations use EFI; FT = High Thrust.\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;\"\u003eF20, F25 and FT‑series variants in multiple shaft lengths and control types.\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 mid‑range torque, quiet operation; High Thrust versions optimized for heavy boats and auxiliary duty.\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;\"\u003eProp pitch and hardware differ from standard F models; EFI engines use different fuel\/filtration components than carb versions.\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 typical guidelines for small four‑stroke outboards. Always confirm the schedule and exact procedures in your Yamaha service manual for your specific model code and usage.\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 #ddd;padding:8px;\"\u003eItem\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;padding:8px;\"\u003eInterval*\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;padding:8px;\"\u003eRemarks\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;padding:8px;\"\u003eParts Link\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eEngine oil + filter\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eFirst 20 hours, then every 100 hours or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eWarm engine before draining; replace crush washer if applicable; use NMMA FC‑W oil grade recommended by Yamaha.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\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: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 intrusion (milky oil) and metal fines; replace drain screw gaskets each service.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha\"\u003eYamaha Parts Collection\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 (often 200 hours)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eVerify plug type\/heat range by model; check gap and look for fouling or lean signs.\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 \/ water separator\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 inline filter; on EFI engines, service any on‑engine microfilters as specified.\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;\"\u003eInspect every 100 hours; replace every 1–2 seasons\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eAny overheat, sand\/silt use, or weak tell‑tale stream warrants earlier replacement.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\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:8px;border-bottom:1px solid #eee;\"\u003eAnodes (internal \u0026amp; external)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eInspect every 50–100 hours; replace when 50% depleted\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eChoose alloy for your water (aluminium\/zinc for salt, magnesium for fresh per OEM guidance).\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-anodes\"\u003eYamaha Anodes\u003c\/a\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eLower unit seal kit (as needed)\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eService if water intrusion found\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eMilky gear oil or leaking prop‑shaft seal requires reseal; pressure\/vacuum test recommended.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\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    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n  \u003cp style=\"font-size:12px;color:#555;margin-top:6px;\"\u003e*Intervals assume typical recreational use; shorten for heavy, commercial, or silty 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\u003eGearcase \u0026amp; Seals: \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-lower-unit-seal-kits\"\u003eYamaha Lower Unit Seal Kits\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\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\u003ePropulsion: \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha-propellers\"\u003eYamaha Propellers\u003c\/a\u003e\n\u003c\/li\u003e\n    \u003cli\u003eGaskets \u0026amp; Sealing: \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:1000px;border-collapse:collapse;\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;padding:8px;\"\u003eSymptom\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;padding:8px;\"\u003eCheck First\u003c\/th\u003e\n        \u003cth style=\"text-align:left;border-bottom:1px solid #ddd;padding:8px;\"\u003eRelated Parts\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eWeak tell‑tale or overheat alarm\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eInspect intake screen for blockage, thermostat condition, and impeller wear; confirm good tell‑tale grommet and hose.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eWater pump kit, thermostat, intake screen, outlet grommet\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; check primer bulb and fuel filter; verify spark plug condition\/gap; on carb models, clean idle circuits.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eFuel filter, spark plugs, fuel line\/bulb, carb service parts\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;\"\u003eInspect prop for damage or wrong pitch; check for fuel restriction; confirm proper timing\/spark and compression.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003ePropeller, fuel filter, spark plugs, air intake components\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eGearcase noise or metal in gear oil\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eDrain and inspect gear oil; check for water intrusion; pressure\/vac test; inspect prop‑shaft seals and bearings.\u003c\/td\u003e\n        \u003ctd style=\"padding:8px;border-bottom:1px solid #eee;\"\u003eLower unit seal kit, prop shaft seals, drain screw gaskets\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 different years or platforms?\u003c\/summary\u003e\n    \u003cp\u003eMany maintenance parts interchange within the same platform and generation (for example, across close HP variants). However, ignition, fuel, and prop components can differ by year, shaft length, or High Thrust gearing. Always confirm with your exact model code and serial.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhen should I replace the impeller?\u003c\/summary\u003e\n    \u003cp\u003eInspect every 100 hours and replace every 1–2 seasons. Replace immediately if you see a weak tell‑tale, any overheat event, or if the motor is run in sandy\/silty water.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should I change gear oil?\u003c\/summary\u003e\n    \u003cp\u003eEvery 100 hours or at least once per season. Check sooner if you notice shifting issues, prop‑shaft fishing line damage, or any signs of water contamination (milky oil).\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat information do I need to confirm part compatibility?\u003c\/summary\u003e\n    \u003cp\u003eProvide the full model code and serial number, shaft length (S\/L\/X), start\/control type (tiller vs. remote, manual vs. electric), and the part type you need. Photos of the nameplate and current part help verify a match.\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 for your Yamaha 4‑Stroke 8–25HP outboard? Browse the main Yamaha collection and use Filter \u0026amp; Sort to narrow by horsepower, year, and category.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/yamaha\" style=\"display:inline-block;margin:6px 0 10px;padding:10px 14px;background:#0a4a7a;color:#fff;text-decoration:none;border-radius:4px;\"\u003eShop Yamaha Parts\u003c\/a\u003e\n  \u003cp style=\"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":[],"url":"https:\/\/seasierra.com\/collections\/yamaha-4-stroke-8-25hp-outboard-engine-parts.oembed","provider":"SeaSierra","version":"1.0","type":"link"}