{"product_id":"water-pump-impeller-gasket-fits-yamaha-40hp-50hp-2-stroke-replaces-663-44315-a0","title":"Water Pump Impeller Gasket – Fits Yamaha 40HP 50HP 2-Stroke (Replaces 663-44315-A0)","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\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis \u003cstrong\u003eWater Pump Impeller Gasket\u003c\/strong\u003e is engineered for Yamaha 2-stroke outboard engines including 40 HP (1984–1994), 50 HP (1984–1987), 50 HP Pro Series (1987–1990), and P50 models (1995–1996). Designed as a direct-fit replacement, this gasket ensures reliable sealing between water pump components to maintain efficient cooling system performance.\u003c\/p\u003e\n\n\u003cp\u003eThis gasket replaces Yamaha OEM part number 663-44315-A0.\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eCritical seal for water pump impeller housing\u003c\/li\u003e\n  \u003cli\u003eApplication-specific fitment for Yamaha 2-stroke outboards\u003c\/li\u003e\n  \u003cli\u003eRecommended replacement during routine water pump 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\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\u003e663-44315-A0\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\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      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eOutboard\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\u003e663-44315-A0\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eOutboard\u003c\/td\u003e\n        \u003ctd\u003e50\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1984–1987\u003c\/td\u003e\n        \u003ctd\u003e663-44315-A0\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003ePro Series 50\u003c\/td\u003e\n        \u003ctd\u003e50\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1987–1990\u003c\/td\u003e\n        \u003ctd\u003e663-44315-A0\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eP50\u003c\/td\u003e\n        \u003ctd\u003e50\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1995–1996\u003c\/td\u003e\n        \u003ctd\u003e663-44315-A0\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\u003eOEM Interchange\u003c\/dt\u003e\n  \u003cdd\u003e663-44315-A0\u003c\/dd\u003e\n  \u003cdt\u003eApplication\u003c\/dt\u003e\n  \u003cdd\u003eWater pump impeller housing seal\u003c\/dd\u003e\n  \u003cdt\u003eCompatible Fuel Types\u003c\/dt\u003e\n  \u003cdd\u003eGasoline\u003c\/dd\u003e\n  \u003cdt\u003eEngine Type\u003c\/dt\u003e\n  \u003cdd\u003e2-Stroke Outboard\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e1 × Water Pump Impeller Gasket\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect the battery and lower unit, then remove the water pump housing to access the impeller and gasket.\u003c\/li\u003e\n  \u003cli\u003eRemove the old impeller gasket carefully; clean both mating surfaces thoroughly to remove debris, corrosion, or old sealant residue.\u003c\/li\u003e\n  \u003cli\u003eInspect the impeller for wear or damage; replace if blades are cracked, torn, or deformed.\u003c\/li\u003e\n  \u003cli\u003ePosition the new gasket dry onto the water pump base plate, aligning all bolt holes and water passages.\u003c\/li\u003e\n  \u003cli\u003eInstall the impeller with the blade tips oriented in the correct rotation direction (consult service manual if unsure).\u003c\/li\u003e\n  \u003cli\u003eApply a thin coat of marine grease to the impeller for easier installation and initial lubrication.\u003c\/li\u003e\n  \u003cli\u003eCarefully lower the pump housing over the impeller, ensuring blades fold smoothly without binding or tearing.\u003c\/li\u003e\n  \u003cli\u003eTorque housing bolts to manufacturer specification in a criss-cross pattern to ensure even gasket compression.\u003c\/li\u003e\n  \u003cli\u003eReinstall the lower unit, reconnect the battery, and run the engine with water supply to verify proper flow and no leaks.\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 when to replace the water pump gasket?\u003c\/summary\u003e\n  \u003cp\u003eReplace the gasket any time you service or rebuild the water pump, or if you notice coolant leaks, overheating, or reduced water flow from the tell-tale. Regular inspection every 2–3 years or 200–300 hours is recommended for outboards in saltwater or heavy-use environments.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eCan I reuse the old gasket?\u003c\/summary\u003e\n  \u003cp\u003eNo. Gaskets compress and conform to mating surfaces during use. Reusing an old gasket can result in improper sealing, leaks, and overheating. Always install a new gasket during water pump service.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eDo I need sealant with this gasket?\u003c\/summary\u003e\n  \u003cp\u003eIn most cases, no additional sealant is required if surfaces are clean and flat. Consult your engine's service manual; some installations call for a thin film of water-resistant gasket sealant to aid sealing on rough or corroded surfaces.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eWill this gasket fit other Yamaha models not listed?\u003c\/summary\u003e\n  \u003cp\u003eThis gasket is confirmed for the engines listed in the compatibility table. For unlisted models, cross-reference OEM part number 663-44315-A0 in your service manual or contact support with your engine serial number to verify fitment.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003cdetails\u003e\n  \u003csummary\u003eWhat causes water pump gaskets to fail?\u003c\/summary\u003e\n  \u003cp\u003eCommon causes include age-related hardening, improper torque during installation, corrosion of mating surfaces, running the engine dry (overheating), and debris in the cooling system. Regular maintenance and flushing help extend gasket life.\u003c\/p\u003e\n\u003c\/details\u003e\n\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\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\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 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\u003ePro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n  \u003cli\u003eFast Global Fulfillment — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n  \u003cli\u003eManufacturer-Direct Value — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":51025604706619,"sku":"2282","price":16.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/12_cd783e04-572c-4c92-8740-4aded4c5e67e.jpg?v=1772928012","url":"https:\/\/seasierra.com\/products\/water-pump-impeller-gasket-fits-yamaha-40hp-50hp-2-stroke-replaces-663-44315-a0","provider":"SeaSierra","version":"1.0","type":"link"}