{"title":"Tohatsu 4-Stroke 8-20HP Outboard Parts","description":"\u003csection id=\"hero\" style=\"max-width:980px;padding:16px 12px;\"\u003e\n  \u003cp\u003eThis page supports Tohatsu 4-Stroke 8–20HP outboard engines. Use it to find compatible parts and service information, including maintenance tips, common replacement items, and troubleshooting guidance. You can also browse the main Tohatsu collection. Scroll to the bottom of the 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.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/tohatsu-outboard-parts\" style=\"display:inline-block;padding:10px 14px;border:1px solid #0a5;border-radius:6px;text-decoration:none;\"\u003eBrowse All Tohatsu Parts\u003c\/a\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"identify-model\" style=\"max-width:980px;padding:16px 12px;\"\u003e\n  \u003ch2\u003eHow to Identify Your 8–20HP Model\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eLocate the nameplate\/serial label on the transom bracket (usually port side) or on the swivel bracket. Record the model code and serial number.\u003c\/li\u003e\n    \u003cli\u003eModel codes typically begin with MFS followed by horsepower (e.g., MFS8, MFS9.8, MFS9.9, MFS15, MFS20). Suffix letters indicate shaft length (S=short, L=long), electric start (E), tiller vs. remote, and other options.\u003c\/li\u003e\n    \u003cli\u003ePlatform cues: 8\/9.8HP models are commonly carbureted twin-cylinder; 9.9\/15\/20HP models are often the newer EFI twin-cylinder platform. Look for an EFI fuel rail and sensors versus a carburetor and choke\/primer.\u003c\/li\u003e\n    \u003cli\u003eUse the exact model and serial to confirm parts such as water pump kits, gearcase seals, and ignition components.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"engine-overview\" style=\"max-width:980px;padding:16px 12px;\"\u003e\n  \u003ch2\u003ePlatform Overview\u003c\/h2\u003e\n  \u003ch3\u003ePortable Twin 8–9.8HP (Carbureted)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;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 style=\"padding:6px 0;\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003e4‑stroke, inline‑2, carbureted; manual or electric start; tiller or remote options.\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;\"\u003eExamples include MFS8 and MFS9.8 variants (short\/long shaft, manual\/electric).\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, simple fuel system, easy dockside service, excellent portability.\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;\"\u003eVerify impeller and gearcase seal kit by model code and shaft length. Prop pitch varies by load and hull.\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003ch3\u003ePortable Twin 9.9–20HP (EFI)\u003c\/h3\u003e\n  \u003ctable style=\"width:100%;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 style=\"padding:6px 0;\"\u003eConfiguration\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003e4‑stroke, inline‑2, EFI; manual or electric start; tiller\/remote, power trim on select variants.\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;\"\u003eExamples include MFS9.9, MFS15, MFS20 EFI variants (S\/L shafts, manual\/electric, tiller\/remote).\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;\"\u003eClean starting, strong mid‑range torque, better fuel economy and altitude compensation vs. carbureted units.\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;\"\u003eUse the model code to match EFI‑specific fuel filters and gaskets. Many props and anodes overlap across 9.9–20HP.\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=\"max-width:980px;padding:16px 12px;\"\u003e\n  \u003ch2\u003eRoutine Maintenance \u0026amp; Service Parts\u003c\/h2\u003e\n  \u003cp\u003eIntervals below are general guidelines for typical recreational use; always follow the official service manual for your specific model and operating conditions.\u003c\/p\u003e\n  \u003ctable style=\"width:100%;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 style=\"padding:6px 0;\"\u003eEngine oil + filter\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eFirst 20 hrs, then every 100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eUse marine 4‑stroke oil per spec; replace filter with each oil change.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\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:6px 0;\"\u003eGear oil (lower unit)\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eEvery 100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eInspect for water intrusion (milky oil) and metal fines. Replace seals if leakage is found.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/tohatsu-lower-unit-seal-kits\"\u003eTohatsu 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;\"\u003eInspect every 100 hrs; replace 200–300 hrs or as needed\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eSet correct gap; replace if fouled, worn, or corroded.\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;\"\u003eEvery 100 hrs or annually\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eReplace more often with ethanol fuel or dirty tanks; keep spare onboard.\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;\"\u003eEvery 2–3 seasons (or 200 hrs)\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eReplace sooner if weak telltale, overheating, or after sand\/silt use.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003e\u003ca href=\"https:\/\/seasierra.com\/collections\/tohatsu-water-pump-repair-kits\"\u003eTohatsu 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 when 50% consumed\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eChoose material for your water (aluminum for brackish\/salt, magnesium for fresh, zinc for traditional salt).\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\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:6px 0;\"\u003ePropeller inspection\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eCheck every outing\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eRemove debris; inspect hub for damage and pitch suitability.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\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=\"max-width:980px;padding:16px 12px;\"\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\/tohatsu-water-pump-repair-kits\"\u003eTohatsu 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\/tohatsu-lower-unit-seal-kits\"\u003eTohatsu 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=\"max-width:980px;padding:16px 12px;\"\u003e\n  \u003ch2\u003eCommon Symptoms \u0026amp; Quick Checks\u003c\/h2\u003e\n  \u003ctable style=\"width:100%;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 style=\"padding:6px 0;\"\u003eWeak telltale or overheat alarm\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eInspect intake screens for debris; verify strong telltale; review service history of impeller.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eWater pump repair 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;\"\u003eUse fresh fuel; prime the system; check inline filter; inspect\/replace spark plugs and plug caps.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eFuel filter, spark plugs, primer bulb, EFI filters (where equipped)\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003ePoor acceleration \/ power loss\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eCheck prop for damage or fouling; verify correct prop pitch; look for fuel restriction or misfire.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003ePropeller, fuel filter, spark plugs\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eNo charging \/ weak battery (electric‑start models)\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eMeasure battery voltage; inspect fuses and wiring; test rectifier\/regulator output if equipped.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eRectifier\/regulator, fuses, wiring connectors\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eGearcase noise or metal in gear oil\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eDrain and inspect gear oil; look for water intrusion; check prop shaft for fishing line cutting seals.\u003c\/td\u003e\n        \u003ctd style=\"padding:6px 0;\"\u003eLower unit seal kit, bearings, shims\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=\"max-width:980px;padding:16px 12px;\"\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\u003eSome items overlap across 8–9.8HP and 9.9–20HP families, but many components differ (cooling, fuel, and gearcase parts). Always confirm by 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\u003eAs a rule of thumb, every 2–3 seasons (or about 200 hours). Replace immediately if the telltale weakens, the engine overheats, or after running in sandy or silty water.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should the lower unit gear oil be changed?\u003c\/summary\u003e\n    \u003cp\u003eEvery 100 hours or annually, and any time you see milky oil, metal shavings, or after an impact or submersion event.\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\u003eProvide the full model code, serial number, shaft length (S\/L\/XL), start\/control type (manual\/electric, tiller\/remote), and a brief description or photo of the part you are replacing.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"cta\" style=\"max-width:980px;padding:16px 12px;\"\u003e\n  \u003cp\u003eReady to find parts? Browse the main Tohatsu collection by horsepower, year, and model to locate compatible components for your 8–20HP four‑stroke.\u003c\/p\u003e\n  \u003ca href=\"https:\/\/seasierra.com\/collections\/tohatsu-outboard-parts\" style=\"display:inline-block;padding:10px 14px;border:1px solid #0a5;border-radius:6px;text-decoration:none;\"\u003eShop Tohatsu Outboard Parts\u003c\/a\u003e\n  \u003cp style=\"font-size:0.95em;color:#333;\"\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":"water-pump-impeller-fits-mercury-tohatsu-8-20-hp-4-stroke-outboards-replaces-47-803748","title":"Aftermarket Water Pump Impeller for Mercury\/Mariner and Tohatsu\/Nissan Outboards – 2-Stroke 9.9–18 HP, 4-Stroke 9.9–20 HP","description":"\u003cstyle\u003e\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n  table.ss-table th {\n    white-space:nowrap;\n    word-break:normal;\n    letter-spacing:normal;\n    font-weight:600;\n    background:#f8fafc;\n  }\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\u003csection\u003e\n  \u003ch2\u003eProduct Details\u003c\/h2\u003e\n  \u003cp\u003eThis aftermarket \u003cstrong\u003ewater pump impeller\u003c\/strong\u003e is designed for selected Mercury\/Mariner and Tohatsu\/Nissan marine outboards. The company application data covers Tohatsu\/Nissan 2-stroke 9.9, 15, and 18 HP engines; Tohatsu 4-stroke MFS9.9, MFS15, and MFS18 engines; Tohatsu 4-stroke 20 HP engines; and Mercury\/Mariner 4-stroke 9.9 HP 209cc, 15 HP, and 20 HP applications.\u003c\/p\u003e\n  \u003cp\u003eUse the reference numbers and model information below as a fitment aid. Outboard water pump components can vary by model family, production year, and serial-number range, so confirm the existing impeller or manufacturer part number before ordering.\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eReplacement water pump impeller for selected 2-stroke and 4-stroke outboards.\u003c\/li\u003e\n    \u003cli\u003eAftermarket replacement listed under Sierra reference \u003cstrong\u003e18-8921\u003c\/strong\u003e.\u003c\/li\u003e\n    \u003cli\u003eSold as \u003cstrong\u003eone impeller only\u003c\/strong\u003e; an impeller key is not included unless specifically stated by the seller.\u003c\/li\u003e\n    \u003cli\u003eNot an OEM component. Brand names and part numbers are used only to identify intended applications and reference compatibility.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n  \u003cp\u003eThe following manufacturer and aftermarket references are listed for cross-referencing. A reference number alone does not replace confirmation of the complete engine model and serial-number conditions.\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 or Source\u003c\/th\u003e\n\u003cth\u003eReference Number\u003c\/th\u003e\n\u003cth\u003eUse\u003c\/th\u003e\n\u003c\/tr\u003e\n      \u003c\/thead\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003ctd\u003eTohatsu\u003c\/td\u003e\n\u003ctd\u003e334-65021-0\u003c\/td\u003e\n\u003ctd\u003eManufacturer reference\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eTohatsu\u003c\/td\u003e\n\u003ctd\u003e334650210M\u003c\/td\u003e\n\u003ctd\u003eManufacturer reference format\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury Marine\u003c\/td\u003e\n\u003ctd\u003e47-803748\u003c\/td\u003e\n\u003ctd\u003eManufacturer reference\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury Marine\u003c\/td\u003e\n\u003ctd\u003e8M0135803\u003c\/td\u003e\n\u003ctd\u003eManufacturer reference\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury Marine\u003c\/td\u003e\n\u003ctd\u003e8M0214944\u003c\/td\u003e\n\u003ctd\u003eAdditional listed reference\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury Marine\u003c\/td\u003e\n\u003ctd\u003e803748\u003c\/td\u003e\n\u003ctd\u003eAdditional listed reference\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury Marine\u003c\/td\u003e\n\u003ctd\u003e803748K01\u003c\/td\u003e\n\u003ctd\u003eAdditional listed reference\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eSierra\u003c\/td\u003e\n\u003ctd\u003e18-8921\u003c\/td\u003e\n\u003ctd\u003eAftermarket reference\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eEvinrude\/Johnson\/OMC\/BRP\u003c\/td\u003e\n\u003ctd\u003e5040046\u003c\/td\u003e\n\u003ctd\u003eAdditional listed 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 is organized by engine family and stroke type. Confirm the exact model and serial number before installation.\u003c\/p\u003e\n  \u003cdiv class=\"ss-table-wrap\"\u003e\n    \u003ctable class=\"ss-table\" aria-label=\"Tohatsu and Nissan Compatibility\"\u003e\n      \u003cthead\u003e\n        \u003ctr\u003e\n          \u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eModel or Application\u003c\/th\u003e\n\u003cth\u003eRated HP\u003c\/th\u003e\n\u003cth\u003eStroke\u003c\/th\u003e\n\u003cth\u003eReference\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\u003eTohatsu\/Nissan\u003c\/td\u003e\n\u003ctd\u003eM9.9, NS9.9 and related applications\u003c\/td\u003e\n\u003ctd\u003e9.9\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e334-65021-0\u003cbr\u003e334650210M\u003c\/td\u003e\n\u003ctd\u003eConfirm the exact model designation.\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eTohatsu\/Nissan\u003c\/td\u003e\n\u003ctd\u003eM15, NS15 and related applications\u003c\/td\u003e\n\u003ctd\u003e15\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e334-65021-0\u003cbr\u003e334650210M\u003c\/td\u003e\n\u003ctd\u003eConfirm the exact model designation.\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eTohatsu\/Nissan\u003c\/td\u003e\n\u003ctd\u003eM18, NS18 and related applications\u003c\/td\u003e\n\u003ctd\u003e18\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e334-65021-0\u003cbr\u003e334650210M\u003c\/td\u003e\n\u003ctd\u003eConfirm the exact model designation.\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eTohatsu\u003c\/td\u003e\n\u003ctd\u003eMFS9.9\u003c\/td\u003e\n\u003ctd\u003e9.9\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e334-65021-0\u003cbr\u003e334650210M\u003c\/td\u003e\n\u003ctd\u003eApplication listed in the company data.\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eTohatsu\u003c\/td\u003e\n\u003ctd\u003eMFS15\u003c\/td\u003e\n\u003ctd\u003e15\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e334-65021-0\u003cbr\u003e334650210M\u003c\/td\u003e\n\u003ctd\u003eApplication listed in the company data.\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eTohatsu\u003c\/td\u003e\n\u003ctd\u003eMFS18\u003c\/td\u003e\n\u003ctd\u003e18\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e334-65021-0\u003cbr\u003e334650210M\u003c\/td\u003e\n\u003ctd\u003eApplication listed in the company data.\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eTohatsu\u003c\/td\u003e\n\u003ctd\u003e20 HP applications\u003c\/td\u003e\n\u003ctd\u003e20\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e334-65021-0\u003cbr\u003e334650210M\u003c\/td\u003e\n\u003ctd\u003eConfirm the exact model and serial number.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"ss-table-wrap\"\u003e\n    \u003ctable class=\"ss-table\" aria-label=\"Mercury and Mariner Compatibility\"\u003e\n      \u003cthead\u003e\n        \u003ctr\u003e\n          \u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eModel or Application\u003c\/th\u003e\n\u003cth\u003eRated HP\u003c\/th\u003e\n\u003cth\u003eStroke\u003c\/th\u003e\n\u003cth\u003eReference\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\u003eMercury\/Mariner\u003c\/td\u003e\n\u003ctd\u003e9.9 HP 209cc applications\u003c\/td\u003e\n\u003ctd\u003e9.9\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e47-803748\u003cbr\u003e8M0135803\u003c\/td\u003e\n\u003ctd\u003eConfirm the 209cc engine configuration.\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n\u003ctd\u003e15 HP applications\u003c\/td\u003e\n\u003ctd\u003e15\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e47-803748\u003cbr\u003e8M0135803\u003c\/td\u003e\n\u003ctd\u003eConfirm the exact model and serial number.\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n\u003ctd\u003e20 HP applications\u003c\/td\u003e\n\u003ctd\u003e20\u003c\/td\u003e\n\u003ctd\u003e4-Stroke\u003c\/td\u003e\n\u003ctd\u003e47-803748\u003cbr\u003e8M0135803\u003c\/td\u003e\n\u003ctd\u003eConfirm the exact model and serial number.\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\n  \u003ch2\u003eTechnical Information\u003c\/h2\u003e\n  \u003cdl\u003e\n    \u003cdt\u003eProduct Type\u003c\/dt\u003e\n    \u003cdd\u003eWater pump impeller\u003c\/dd\u003e\n    \u003cdt\u003eProduct Configuration\u003c\/dt\u003e\n    \u003cdd\u003eSingle impeller\u003c\/dd\u003e\n    \u003cdt\u003eAftermarket Reference\u003c\/dt\u003e\n    \u003cdd\u003eSierra 18-8921\u003c\/dd\u003e\n    \u003cdt\u003ePrimary Manufacturer Reference\u003c\/dt\u003e\n    \u003cdd\u003eTohatsu 334-65021-0 \/ 334650210M\u003c\/dd\u003e\n    \u003cdt\u003eAdditional Manufacturer References\u003c\/dt\u003e\n    \u003cdd\u003eMercury 47-803748, 8M0135803, 8M0214944, 803748, 803748K01; Evinrude\/Johnson\/OMC\/BRP 5040046\u003c\/dd\u003e\n    \u003cdt\u003eApplication Range\u003c\/dt\u003e\n    \u003cdd\u003eSelected 2-stroke 9.9–18 HP and 4-stroke 9.9–20 HP outboards, subject to exact model and serial-number confirmation\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 aftermarket water pump impeller\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \u003cp\u003e\u003cstrong\u003eImportant:\u003c\/strong\u003e The impeller key is not included with this single-impeller product. Reuse of an old key is not recommended if it is worn, damaged, or does not fit securely in the shaft keyway.\u003c\/p\u003e\n\n  \u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n  \u003col\u003e\n    \u003cli\u003eDisconnect the battery and follow the outboard manufacturer’s service precautions.\u003c\/li\u003e\n    \u003cli\u003ePlace the engine in neutral and remove the lower unit according to the service manual for the specific model.\u003c\/li\u003e\n    \u003cli\u003eRemove the water pump housing and take note of the impeller, key, housing, and base-plate orientation.\u003c\/li\u003e\n    \u003cli\u003eRemove the old impeller and inspect the housing, wear plate, key, and driveshaft keyway for damage or excessive wear.\u003c\/li\u003e\n    \u003cli\u003eInstall the correct key for the engine, then align the replacement impeller with the keyway.\u003c\/li\u003e\n    \u003cli\u003eReinstall the water pump housing using the manufacturer’s specified blade orientation and assembly procedure.\u003c\/li\u003e\n    \u003cli\u003eReassemble the lower unit, restore the correct lubricant level, and test the cooling-water flow with an appropriate water supply.\u003c\/li\u003e\n    \u003cli\u003eStop the engine immediately if the tell-tale stream is weak or absent, or if an overheating warning occurs.\u003c\/li\u003e\n  \u003c\/ol\u003e\n\n  \u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow do I confirm this impeller fits my engine?\u003c\/summary\u003e\n    \u003cp\u003eCompare your original impeller and manufacturer part number with the reference matrix, then confirm the complete engine brand, model, stroke type, horsepower, and serial-number range. Do not rely on horsepower alone.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs this a complete water pump kit?\u003c\/summary\u003e\n    \u003cp\u003eNo. This listing is for one water pump impeller only. It does not include an impeller key, water pump housing, wear plate, gasket, or other pump components.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat are common signs of a worn impeller?\u003c\/summary\u003e\n    \u003cp\u003eA weak or missing tell-tale stream, overheating, or reduced cooling performance can indicate a worn, damaged, incorrectly installed, or obstructed water pump impeller. Inspect the complete cooling system before replacing parts.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eShould I replace the impeller key?\u003c\/summary\u003e\n    \u003cp\u003eInspect the key and keyway during service. Replace the key if it is worn, damaged, loose, or otherwise unsuitable. The correct key is not included with this single-impeller product.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs this an OEM part?\u003c\/summary\u003e\n    \u003cp\u003eNo. This is an aftermarket replacement impeller. The listed manufacturer and aftermarket numbers are reference numbers for identifying intended applications and compatibility.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eCan the same reference number fit both 2-stroke and 4-stroke engines?\u003c\/summary\u003e\n    \u003cp\u003eSome catalog references are listed across different engine families, but the complete model and serial-number conditions still determine fitment. Verify the application before installation.\u003c\/p\u003e\n  \u003c\/details\u003e\n\n  \u003ch2\u003eSafety \u0026amp; Important Information\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eVerify the original part, reference number, dimensions, and engine application before ordering.\u003c\/li\u003e\n    \u003cli\u003eDo not operate an outboard with insufficient cooling-water flow.\u003c\/li\u003e\n    \u003cli\u003eFollow the manufacturer’s service manual for lower-unit removal, torque values, lubrication, and testing.\u003c\/li\u003e\n    \u003cli\u003eProfessional installation is recommended when the correct model, key, or installation procedure is uncertain.\u003c\/li\u003e\n    \u003cli\u003eThis is an aftermarket replacement and is not manufactured or endorsed by Mercury, Mariner, Tohatsu, Nissan, Evinrude, Johnson, OMC, BRP, or Sierra.\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 service and repair.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eApplication-Focused Listings\u003c\/strong\u003e — Reference numbers and model information are provided to help customers verify fitment.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCustomer Support\u003c\/strong\u003e — Contact support with your engine model, horsepower, stroke type, serial number, and existing part number when compatibility is uncertain.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723981984059,"sku":"17IT004","price":14.08,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/17IT0041_702bbbac-cf6d-488a-b538-5d75c62d8711.jpg?v=1763039288"}],"url":"https:\/\/seasierra.com\/collections\/tohatsu-4-stroke-8-20hp-outboard-parts.oembed","provider":"SeaSierra","version":"1.0","type":"link"}