{"product_id":"water-pump-impeller-kit-fits-yamaha-25-70-hp-outboards-replaces-663-44311-02","title":"Water Pump Impeller Kit – Fits Yamaha 25–70 HP Outboards (Replaces 663-44311-02)","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 25–70 HP Outboards (Replaces 663-44311-02)\u003c\/strong\u003e is a comprehensive solution designed to restore the cooling system on Yamaha 2-stroke outboard motors from 25 to 70 HP (1984–2005). The kit provides all necessary components for a complete water pump assembly rebuild, ensuring your engine maintains proper operating temperatures.\u003c\/p\u003e\n\u003cp\u003eIt serves as a direct interchange for several Yamaha part numbers, including 663-W0078-01, 663-W0078-A0, 6H3-W0078-02-00, and 6H3-W0078-A0-00.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eEngineered for direct OEM replacement installation.\u003c\/li\u003e\n\u003cli\u003eMaintains proper cooling water circulation for outboard motors.\u003c\/li\u003e\n\u003cli\u003eIncludes impeller, gaskets, plates, and hardware for a full 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.\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\u003e663-W0078-01\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e663-W0078-A0\u003c\/td\u003e\n      \u003c\/tr\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\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-A0-00\u003c\/td\u003e\n      \u003c\/tr\u003e\n       \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e6H4-W0078-00\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\u003cp\u003eThis kit fits a wide range of Yamaha 2-stroke outboards. Please verify your specific model and year against the compatibility list.\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\u003eC-55\u003c\/td\u003e\n        \u003ctd\u003e55\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1991–1995\u003c\/td\u003e\n        \u003ctd\u003e663-W0078-01, 663-W0078-A0\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eCV-55\u003c\/td\u003e\n        \u003ctd\u003e55\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1989\u003c\/td\u003e\n        \u003ctd\u003e663-W0078-01, 663-W0078-A0\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eC-60\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\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eC-70\u003c\/td\u003e\n        \u003ctd\u003e70\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2000–2001\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\u003eP-60\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\u003eT-50\u003c\/td\u003e\n        \u003ctd\u003e50\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1997–2001, 2003, 2005\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\u003eT-60\u003c\/td\u003e\n        \u003ctd\u003e60\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2003–2005\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\u003e60\u003c\/td\u003e\n        \u003ctd\u003e60\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e2003\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\u003eT50\u003c\/td\u003e\n        \u003ctd\u003e50\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1996\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-A0-00\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n       \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eC55 (Drive 2)\u003c\/td\u003e\n        \u003ctd\u003e55\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1991–1994\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-A0-00\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eCV55 (Drive 2)\u003c\/td\u003e\n        \u003ctd\u003e55\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1989\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-A0-00\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eP60\u003c\/td\u003e\n        \u003ctd\u003e60\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1991\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-A0-00\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n       \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e60\u003c\/td\u003e\n        \u003ctd\u003e60\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1984–1991\u003c\/td\u003e\n        \u003ctd\u003e6H3-W0078-A0-00\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e40\u003c\/td\u003e\n        \u003ctd\u003e40\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1984–1994\u003c\/td\u003e\n        \u003ctd\u003e6H4-W0078-00\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e50\u003c\/td\u003e\n        \u003ctd\u003e50\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1986–1994\u003c\/td\u003e\n        \u003ctd\u003e6H4-W0078-00\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003ePro 50\u003c\/td\u003e\n        \u003ctd\u003e50\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1991–1994\u003c\/td\u003e\n        \u003ctd\u003e6H4-W0078-00\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\u003eDirect OEM replacement\u003c\/dd\u003e\n  \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eMaintains proper cooling water circulation for outboard motors\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 (663-44315-A0-00)\u003c\/li\u003e\n  \u003cli\u003e1 x Cartridge Outer Plate (663-44323-00-00)\u003c\/li\u003e\n  \u003cli\u003e1 x Cartridge Gasket (663-44324-A0-00)\u003c\/li\u003e\n  \u003cli\u003e\u003cspan style=\"color:#d0021b;\"\u003e2 x Bolts (97095-08055-00)\u003c\/span\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003cspan style=\"color:#d0021b;\"\u003e2 x Bolts (97095-08045-00)\u003c\/span\u003e\u003c\/li\u003e\n  \u003cli\u003e1 x Water Seal Damper 2 (663-44366-00-00)\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 negative battery cable before beginning work.\u003c\/li\u003e\n  \u003cli\u003eRemove the lower unit (gearcase) from the outboard’s midsection.\u003c\/li\u003e\n  \u003cli\u003eUnbolt and carefully remove the existing water pump housing. Note the orientation of the bolts.\u003c\/li\u003e\n  \u003cli\u003eInspect the housing assembly for cracks, scoring, or warping. Clean all gasket surfaces thoroughly.\u003c\/li\u003e\n  \u003cli\u003eRemove the old impeller, woodruff key, wear plate, gaskets, and seals.\u003c\/li\u003e\n  \u003cli\u003eInstall the new water seal damper and cartridge gasket onto the clean housing plate.\u003c\/li\u003e\n  \u003cli\u003ePlace the new woodruff key onto the flat spot on the driveshaft.\u003c\/li\u003e\n  \u003cli\u003eSlide the new impeller down the driveshaft, aligning its keyway with the key. Rotate the driveshaft clockwise to help seat the impeller vanes correctly.\u003c\/li\u003e\n  \u003cli\u003eInstall the new cartridge insert and outer plate over the impeller.\u003c\/li\u003e\n  \u003cli\u003eApply the new water pump gasket and reinstall the housing using the new bolts. Tighten bolts to the manufacturer's specified torque in a crisscross pattern.\u003c\/li\u003e\n  \u003cli\u003eReinstall the lower unit, ensuring the driveshaft and water tube align correctly.\u003c\/li\u003e\n  \u003cli\u003eReconnect the battery, start the engine in water, and confirm a steady stream of water from the tell-tale outlet.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are the signs of a failing water pump impeller?\u003c\/summary\u003e\n  \u003cp\u003eCommon signs include a weak or intermittent water stream from the \"tell-tale\" outlet, engine overheating alarms, and in severe cases, steam from the exhaust. Reduced top-end speed or engine performance can also indicate poor cooling.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow often should I replace my outboard's impeller?\u003c\/summary\u003e\n  \u003cp\u003eAs a general preventative maintenance rule, it is recommended to replace the impeller every 1-2 years or every 100-200 hours of operation, whichever comes first. Usage in saltwater or sandy\/silty conditions may require more frequent changes.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eDoes this kit include the water pump housing?\u003c\/summary\u003e\n  \u003cp\u003eThis kit includes the internal components required for a rebuild (impeller, gaskets, plates, etc.) but does not include the main upper or lower water pump housing. You will typically reuse your existing housing if it is not cracked, warped, or excessively scored.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is the difference between the listed OEM part numbers like 663-W0078-01 and 6H3-W0078-A0-00?\u003c\/summary\u003e\n  \u003cp\u003eThese different numbers often represent superseded parts. Manufacturers update parts over time for various reasons, creating a chain where a newer number replaces an older one. This aftermarket kit is designed to be-a cross-reference for all listed equivalents.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this a complete kit for the job?\u003c\/summary\u003e\n  \u003cp\u003eYes, this kit is assembled to include all the common wear items needed for a standard water pump service. You receive the impeller, gaskets, plates, damper seal, key, and new bolts as pictured and listed.\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\/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":50723807723835,"sku":"17KY010","price":46.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/Water_Pump_Impeller_Kit_for_Yamaha25_to_70_HP_663-44311-02_-_JLM_MARINE-8288992.jpg?v=1763032289","url":"https:\/\/seasierra.com\/products\/water-pump-impeller-kit-fits-yamaha-25-70-hp-outboards-replaces-663-44311-02","provider":"SeaSierra","version":"1.0","type":"link"}