{"product_id":"water-pump-impeller-kit-fits-yamaha-f50a-4-stroke-replaces-yamaha-6bg-w0078-01-00-sierra-18-3434","title":"Water Pump Impeller Kit – Fits Yamaha F50A 4-Stroke (Replaces Yamaha 6BG-W0078-01-00, Sierra 18-3434)","description":"\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\u003csection\u003e\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis \u003cstrong\u003eWater Pump Impeller Kit\u003c\/strong\u003e provides a complete solution for servicing the water pump on Yamaha 4-stroke 40–50 HP outboards, including models F40, F50A (1991–2007), F30LA, and F40LA. It is designed to restore cooling system performance and prevent engine overheating.\u003c\/p\u003e\n\u003cp\u003eIt serves as a direct replacement for Yamaha part numbers 6BG-W0078-01-00 and 6BG-W0078-00-00, as well as aftermarket equivalents Sierra 18-3434, JLM YHJB-6BG, and SeaSierra 63DW007800.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eDesigned for installation in the lower unit\/gear case.\u003c\/li\u003e\n\u003cli\u003eThe kit includes the impeller, impeller key, and all necessary gaskets for a complete repair.\u003c\/li\u003e\n\u003cli\u003eRestores cooling system efficiency to factory specifications.\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\u003e6BG-W0078-01-00\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e6BG-W0078-00-00\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-3434\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eJLM\u003c\/td\u003e\n        \u003ctd\u003eYHJB-6BG\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSeaSierra\u003c\/td\u003e\n        \u003ctd\u003e63DW007800\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 is designed for a range of Yamaha 4-stroke and select 2-stroke outboard models. Please verify your specific engine against the details provided.\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\u003eF50A\u003c\/td\u003e\n        \u003ctd\u003e50\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1991–2007\u003c\/td\u003e\n        \u003ctd\u003e6BG-W0078-01-00\u003c\/td\u003e\n        \u003ctd\u003eIncluded in Yamaha Maintenance Kit\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eF40B\u003c\/td\u003e\n        \u003ctd\u003e40\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e6BG-W0078-01-00\u003c\/td\u003e\n        \u003ctd\u003e-\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eF30LA\u003c\/td\u003e\n        \u003ctd\u003e30\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e6BG-W0078-01-00\u003c\/td\u003e\n        \u003ctd\u003e-\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eF40LA\u003c\/td\u003e\n        \u003ctd\u003e40\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e6BG-W0078-01-00\u003c\/td\u003e\n        \u003ctd\u003e-\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eE40X, 40X\u003c\/td\u003e\n        \u003ctd\u003e40\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e6BG-W0078-01-00\u003c\/td\u003e\n        \u003ctd\u003eAlso fits some 2-stroke models\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003eF25B\u003c\/td\u003e\n        \u003ctd\u003e25\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n        \u003ctd\u003e6BG-W0078-01-00\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 Repair Kit\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eLower Unit\/Gear Case\u003c\/dd\u003e\n  \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eIncludes impeller key and necessary gaskets\u003c\/dd\u003e\n  \u003cdt\u003eWarranty\u003c\/dt\u003e\n\u003cdd\u003eVaries by manufacturer\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 Water Pump Repair Kit (6BG-W0078-01-00)\u003c\/li\u003e\n\u003cli\u003e1 x Impeller (\u003cspan style=\"color:#d0021b;\"\u003e6H4-44352-02\u003c\/span\u003e)\u003c\/li\u003e\n\u003cli\u003eImpeller Key\u003c\/li\u003e\n\u003cli\u003eNecessary Gaskets and O-rings\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 for safety.\u003c\/li\u003e\n\u003cli\u003eDrain the gearcase oil into a suitable container.\u003c\/li\u003e\n\u003cli\u003eShift the outboard into neutral and remove the shift rod connector bolt or pin.\u003c\/li\u003e\n\u003cli\u003eUnbolt and carefully lower the gearcase (lower unit) from the outboard's midsection.\u003c\/li\u003e\n\u003cli\u003eRemove the water pump housing bolts and lift the housing off the driveshaft.\u003c\/li\u003e\n\u003cli\u003eRemove the old impeller, woodruff key, wear plate, and gaskets. Note their orientation.\u003c\/li\u003e\n\u003cli\u003eThoroughly clean all mating surfaces, removing any old gasket material or sealant.\u003c\/li\u003e\n\u003cli\u003eInstall the new gaskets, wear plate, and woodruff key onto the driveshaft.\u003c\/li\u003e\n\u003cli\u003eSlide the new impeller onto the driveshaft, turning the shaft clockwise to help seat the impeller vanes correctly inside the housing.\u003c\/li\u003e\n\u003cli\u003eApply a light coat of marine grease to the inside of the pump cup and reinstall the housing. Tighten bolts to the manufacturer's torque specifications.\u003c\/li\u003e\n\u003cli\u003eReassemble the lower unit to the engine, ensuring the water tube, driveshaft splines, and shift shaft are correctly aligned.\u003c\/li\u003e\n\u003cli\u003eRefill the gearcase with fresh oil. Once assembled, start the engine in water and verify a steady stream of water from the tell-tale port.\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 engine?\u003c\/summary\u003e\n  \u003cp\u003eCheck the \"Engine \u0026amp; Model Compatibility\" table on this page. Confirm your engine model, horsepower, and year range. If you are unsure, compare the part numbers in the \"Part Number Matrix\" with your service manual or original part.\u003c\/p\u003e\n\u003c\/details\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 no water stream from the \"tell-tale\" port, engine overheating alarms, steam from the exhaust, and reduced engine performance.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow often should I replace my water pump impeller?\u003c\/summary\u003e\n  \u003cp\u003eAs a general maintenance rule, it is recommended to inspect the impeller annually and replace it every 1-2 years or every 100-200 hours of use, depending on operating conditions (e.g., saltwater vs. freshwater, high-silt environments).\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is the difference between 6BG-W0078-01-00 and 6BG-W0078-00-00?\u003c\/summary\u003e\n  \u003cp\u003eThe part number 6BG-W0078-01-00 is a supersession, meaning it's the newer, direct replacement for the older 6BG-W0078-00-00 part number. They are functionally interchangeable for the listed applications.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eCan I use this kit for a 2-stroke model?\u003c\/summary\u003e\n  \u003cp\u003eWhile the primary application is for 4-stroke engines, it also fits some 2-stroke models like the Yamaha E40X and 40X as noted in the compatibility table. Always verify your specific model and part number before ordering.\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). It is built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 certified facility. All parts are batch-inspected for quality and 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 is 5–15 days for most locations. Standard shipping is free; expedited options will appear at checkout if they are available for your region.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWarranty \u0026amp; returns\u003c\/summary\u003e\n  \u003cp\u003eThis product is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter any issues, please contact our support team with your order details. Returns are accepted within our standard window for unused items in their 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 before purchase. If anything differs—even if your model appears compatible—do not order.\u003c\/li\u003e\n\u003cli\u003eThis is an aftermarket replacement component, not an OEM part. Brand names and part numbers are used for identification purposes only.\u003c\/li\u003e\n\u003cli\u003eProfessional installation is highly recommended for safety and to ensure a proper seal and optimal 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 rigorously tested for real-world reliability.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFast Global Fulfillment\u003c\/strong\u003e — We offer free standard delivery to most regions with an average transit time of 5–15 days.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — Our parts deliver fair pricing without compromising on materials, quality control, or performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723806740795,"sku":"23KY710","price":69.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/23KY710_2_c173d1e5-fca1-4e49-af7a-94a801412f10.jpg?v=1763032274","url":"https:\/\/seasierra.com\/products\/water-pump-impeller-kit-fits-yamaha-f50a-4-stroke-replaces-yamaha-6bg-w0078-01-00-sierra-18-3434","provider":"SeaSierra","version":"1.0","type":"link"}