{"product_id":"water-pump-impeller-kit-fits-yamaha-20d-25d-25n-2-stroke-outboards-replaces-yamaha-6l2-w0078-00-00-sierra-18-3431-mercury-879137","title":"Water Pump Impeller Kit – Fits Yamaha 20D\/25D\/25N 2-Stroke Outboards (Replaces Yamaha 6L2-W0078-00-00, Sierra 18-3431, Mercury 879137)","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;       \/* Do not wrap *\/\n    word-break:normal;        \/* Don’t break words *\/\n    letter-spacing:normal;    \/* Prevent theme styles from stretching letters *\/\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\u003eWater Pump Impeller Kit – Fits Yamaha 20D\/25D\/25N 2-Stroke Outboards (Replaces 6L2-W0078-00-00)\u003c\/strong\u003e is designed for Yamaha 2-stroke 20HP and 25HP outboards manufactured between 1988–2004, including the 20D, 25D, and 25N models. This kit provides all necessary components to restore your engine's cooling system performance.\u003c\/p\u003e\n\u003cp\u003eIt serves as a direct replacement for Yamaha 6L2-W0078-00-00, Sierra 18-3431, and Mercury 879137, ensuring a precise fit and function.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eEngineered for a drop-in installation.\u003c\/li\u003e\n\u003cli\u003eThe kit provides essential components for a water pump rebuild but does not include the pump housing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\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      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e6L2-W0078-00-00\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-3431\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e879137\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\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Engine \u0026amp; 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\u003eYears\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\u003e20D\u003c\/td\u003e\n        \u003ctd\u003e20\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1996–1997\u003c\/td\u003e\n        \u003ctd\u003e6L2-W0078-00-00\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e25D\/25N\u003c\/td\u003e\n        \u003ctd\u003e25\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1988–1998, 2000, 2003–2004\u003c\/td\u003e\n        \u003ctd\u003e6L2-W0078-00-00\u003c\/td\u003e\n        \u003ctd\u003e\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\u003eWater Pump Impeller Kit\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDrop-in replacement\u003c\/dd\u003e\n  \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eDoes not include pump housing\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 Cartridge Outer Plate (6L2-44323-00-00)\u003c\/li\u003e\n  \u003cli\u003e1 x O-Ring (93210-45161-00)\u003c\/li\u003e\n  \u003cli\u003e1 x Impeller (6L2-44352-00-00)\u003c\/li\u003e\n  \u003cli\u003e1 x Cartridge Insert (6L2-44322-00-00)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cspan style=\"color:#d0021b;\"\u003e4 x\u003c\/span\u003e Bolts (97095-06040-00)\u003c\/li\u003e\n  \u003cli\u003e1 x Woodruff Key (90280-03024-00)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cspan style=\"color:#d0021b;\"\u003e4 x\u003c\/span\u003e Washers (92990-06600-00)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect the battery and remove the engine cover. Disconnect the shift linkage from the lower unit.\u003c\/li\u003e\n  \u003cli\u003eRemove the bolts securing the lower unit (gearcase) to the upper casing and carefully lower it.\u003c\/li\u003e\n  \u003cli\u003eUnbolt and remove the water pump housing to expose the old impeller. Note the direction of the old impeller's vanes.\u003c\/li\u003e\n  \u003cli\u003eClean the housing interior and inspect the insert and base plate for wear, replacing if necessary.\u003c\/li\u003e\n  \u003cli\u003eInstall the new Woodruff key into the driveshaft slot. Align the new impeller with the key and slide it down.\u003c\/li\u003e\n  \u003cli\u003eApply a light coat of marine grease or soap-and-water solution to the inside of the housing and on the impeller.\u003c\/li\u003e\n  \u003cli\u003eInstall the new impeller, turning the driveshaft clockwise to bed the vanes correctly inside the housing.\u003c\/li\u003e\n  \u003cli\u003eReinstall the water pump housing, outer plate, and any new gaskets\/O-rings provided. Tighten bolts to manufacturer specifications.\u003c\/li\u003e\n  \u003cli\u003eReattach the lower unit to the engine, reconnect the shift linkage, and test the engine in water to verify proper water flow.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\u003csummary\u003eHow do I know if this kit fits my engine?\u003c\/summary\u003e\u003cp\u003eThis kit is specifically for Yamaha 2-stroke 20HP and 25HP outboards (models 20D, 25D, 25N) from 1988–2004. Please verify your engine model and year of manufacture against the 'Engine \u0026amp; Model Compatibility' table. Do not purchase if your model is not listed.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eDoes this kit include the water pump housing?\u003c\/summary\u003e\u003cp\u003eNo, this is an impeller repair kit and does not include the metal or plastic pump housing. It includes the impeller and associated gaskets, plates, and hardware required for a standard replacement.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat are the signs of a failing water pump impeller?\u003c\/summary\u003e\u003cp\u003eCommon symptoms include a weak or intermittent water stream from the \"telltale\" outlet, engine overheating alerts, and, in severe cases, steam from the exhaust. Reduced water pressure is the first sign of a worn impeller.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eHow often should I replace my outboard's impeller?\u003c\/summary\u003e\u003cp\u003eFor most recreational boaters, it is recommended to replace the water pump impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. Refer to your engine's service manual for specific maintenance intervals.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eCan I install this kit myself?\u003c\/summary\u003e\u003cp\u003eWhile installation is possible for those with mechanical experience, we recommend professional installation to ensure safety and correct function. The process involves removing the lower unit, which can be complex. Incorrect installation can lead to engine damage from overheating.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\u003cp\u003eThis listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eShipping speed \u0026amp; cost?\u003c\/summary\u003e\u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWarranty \u0026amp; returns?\u003c\/summary\u003e\u003cp\u003eCovered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused \u0026amp; in original condition). See our policy page or reach out for instructions.\u003c\/p\u003e\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eVerify images\/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.\u003c\/li\u003e\n  \u003cli\u003eThis is an aftermarket replacement, not an OEM component.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended for safety and performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePro-Grade Standards\u003c\/strong\u003e — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFast Global Fulfillment\u003c\/strong\u003e — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723797664059,"sku":"17KY001","price":35.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/Water_Pump_Impeller_Kit_for_Yamaha_20D_25D_25N_6L2-W0078-00-00_-_JLM_MARINE-8288800.jpg?v=1763032027","url":"https:\/\/seasierra.com\/products\/water-pump-impeller-kit-fits-yamaha-20d-25d-25n-2-stroke-outboards-replaces-yamaha-6l2-w0078-00-00-sierra-18-3431-mercury-879137","provider":"SeaSierra","version":"1.0","type":"link"}