{"product_id":"water-pump-repair-kit-fits-yamaha-50-70-hp-outboards-replaces-6h3-w0078-02-00-18-3465","title":"Water Pump Repair Kit – Fits Yamaha 50-70 HP Outboards (Replaces 6H3-W0078-02-00, 18-3465)","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 Repair Kit\u003c\/strong\u003e is engineered for cooling system maintenance on a range of Yamaha outboards. It is designed to fit specific Yamaha 2-Stroke models from 60 HP to 70 HP (1997–2003) and 4-Stroke T50 \u0026amp; T60 High Thrust models (1996–2023), ensuring reliable performance and engine protection.\u003c\/p\u003e\n\u003cp\u003eThis kit serves as a direct replacement for Yamaha part number 6H3-W0078-02-00 and Sierra 18-3465.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eDesigned for comprehensive cooling system maintenance.\u003c\/li\u003e\n  \u003cli\u003eInstalls in the lower unit gearcase.\u003c\/li\u003e\n  \u003cli\u003eIncludes key components like impeller, gaskets, and hardware for a complete service.\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 suppliers.\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\u003e6H3-W0078-02-00\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-3465\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 and year in the table below to ensure accurate fitment.\u003c\/p\u003e\n\u003cp\u003eThis kit is verified for compatibility with the following Yamaha outboard motors.\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\u003eT50\u003c\/td\u003e\n        \u003ctd\u003e50\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1996–2023\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-02-00\u003c\/td\u003e\n        \u003ctd\u003eHigh Thrust models\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eT60\u003c\/td\u003e\n        \u003ctd\u003e60\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1997–2023\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-02-00\u003c\/td\u003e\n        \u003ctd\u003eHigh Thrust models\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e60\u003c\/td\u003e\n        \u003ctd\u003e60\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1997–2003\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-02-00\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n       \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eC60\u003c\/td\u003e\n        \u003ctd\u003e60\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1997–2001\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-02-00\u003c\/td\u003e\n        \u003ctd\u003eCommercial models\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eP60\u003c\/td\u003e\n        \u003ctd\u003e60\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1997–1999\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-02-00\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e70\u003c\/td\u003e\n        \u003ctd\u003e70\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1997–2003\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-02-00\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eC70\u003c\/td\u003e\n        \u003ctd\u003e70\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1997–2003\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-02-00\u003c\/td\u003e\n        \u003ctd\u003eCommercial models\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 Repair Kit\u003c\/dd\u003e\n    \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eLower Unit \/ Gearcase\u003c\/dd\u003e\n    \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eDesigned for cooling system maintenance\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 Insert (663-44322-00-00)\u003c\/li\u003e\n    \u003cli\u003e1 x Impeller (6H3-44352-00-00)\u003c\/li\u003e\n    \u003cli\u003e1 x Water Pump Gasket 1 (6H3-44315-A0-00)\u003c\/li\u003e\n    \u003cli\u003e1 x Cartridge Outer Plate (6H3-44323-00-00)\u003c\/li\u003e\n    \u003cli\u003e1 x Cartridge Gasket (6H3-44324-A0-00)\u003c\/li\u003e\n    \u003cli\u003e1 x Water Pump Gasket 2 (688-44316-A0-00)\u003c\/li\u003e\n    \u003cli\u003e1 x O-Ring (93210-46044-00)\u003c\/li\u003e\n    \u003cli\u003e\u003cspan style=\"color:#d0021b;\"\u003e2 x Bolts, With Washer (90119-08M14-00)\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cspan style=\"color:#d0021b;\"\u003e2 x Bolts, With Washer (90119-08M33-00)\u003c\/span\u003e\u003c\/li\u003e\n    \u003cli\u003e1 x Woodruff Key (90280-03M03-00)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n    \u003cli\u003eDisconnect the battery and shift the outboard into neutral.\u003c\/li\u003e\n    \u003cli\u003eRemove the lower unit (gearcase) by unfastening the mounting bolts located above the anti-cavitation plate.\u003c\/li\u003e\n    \u003cli\u003ePlace the lower unit on a suitable workbench. Locate and unbolt the water pump housing.\u003c\/li\u003e\n    \u003cli\u003eRemove the old impeller, gaskets, wear plate, and housing components. Clean all surfaces thoroughly.\u003c\/li\u003e\n    \u003cli\u003eInstall the new gasket, wear plate, and Woodruff key on the driveshaft.\u003c\/li\u003e\n    \u003cli\u003eSlide the new impeller onto the driveshaft, rotating it clockwise to align the blades.\u003c\/li\u003e\n    \u003cli\u003eInstall the new housing, cartridge insert, and O-rings as supplied in the kit.\u003c\/li\u003e\n    \u003cli\u003eSecurely fasten the water pump housing with the new bolts, applying recommended torque settings.\u003c\/li\u003e\n    \u003cli\u003eReinstall the lower unit, ensuring the water tube and driveshaft are properly aligned. Secure the mounting bolts.\u003c\/li\u003e\n    \u003cli\u003eReconnect the battery and test the engine with a reliable water source to verify proper cooling system function.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I know if this kit fits my Yamaha outboard?\u003c\/summary\u003e\n  \u003cp\u003eThis kit is designed for specific Yamaha engines. Verify your complete model number and year against the compatibility table provided on this page. Do not rely on horsepower alone. Cross-referencing your old part number with the ones listed in our Part Number Matrix (6H3-W0078-02-00) is the most reliable method.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are the signs of a failing water pump?\u003c\/summary\u003e\n  \u003cp\u003eCommon symptoms include the engine overheating at idle or low speeds, a weak or inconsistent \"tell-tale\" water stream, or a discolored\/melted water pump housing found during inspection. Gradual loss of cooling efficiency is the primary indicator.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow often should I replace my water pump impeller and kit components?\u003c\/summary\u003e\n  \u003cp\u003eAs a best practice for preventative maintenance, outboard water pump impellers should be inspected annually and replaced every 1-2 years or 100-200 hours of operation, depending on usage conditions (e.g., more frequently in sandy or saltwater environments). Replacing the full kit is recommended to ensure all wear components are new.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eDoes this kit include everything I need for the job?\u003c\/summary\u003e\n  \u003cp\u003eYes, this is a comprehensive repair kit that includes the impeller, housing insert, gaskets, plate, O-ring, Woodruff key, and the necessary installation bolts as listed in the \"What's in the Box\" section. You will not need to purchase these core components separately.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs it difficult to install this kit myself?\u003c\/summary\u003e\n  \u003cp\u003eInstallation is suitable for individuals with moderate mechanical skill and the proper tools. The process involves removing the lower unit (gearcase). If you are unfamiliar with this procedure, we recommend consulting a service manual for your specific engine or hiring a professional marine mechanic.\u003c\/p\u003e precluded\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhy is a consistent water stream from the tell-tale important?\u003c\/summary\u003e\n  \u003cp\u003eThe \"tell-tale\" stream is a visual indicator that the water pump is successfully circulating water through the engine's cooling passages. A strong, steady stream indicates the pump is functioning correctly. A weak, intermittent, or non-existent stream signals a problem that requires immediate attention to prevent overheating.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\n  \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\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eShipping speed \u0026amp; cost?\u003c\/summary\u003e\n  \u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWarranty \u0026amp; returns?\u003c\/summary\u003e\n  \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\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eVerify images and specifications against 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 quality control.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723979002171,"sku":"23KY084","price":19.8,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/23KY0841_d42a661c-0aee-4ed3-b481-67dd0107759e.jpg?v=1763039149","url":"https:\/\/seasierra.com\/products\/water-pump-repair-kit-fits-yamaha-50-70-hp-outboards-replaces-6h3-w0078-02-00-18-3465","provider":"SeaSierra","version":"1.0","type":"link"}