{"product_id":"water-pump-impeller-kit-fits-yamaha-25hp-40hp-replaces-66t-w0078-a0-18-3432-89890","title":"Water Pump Impeller Kit – Fits Yamaha 25HP-40HP (Replaces 66T-W0078-A0, 18-3432, 89890)","description":"\u003csection id=\"product-details\"\u003e\n  \u003ch2\u003eProduct Details\u003c\/h2\u003e\n  \u003cp\u003eThis aftermarket \u003cstrong\u003eWater Pump Impeller Kit – Fits Yamaha 25HP-40HP Outboards (Replaces 66T-W0078-A0)\u003c\/strong\u003e is designed for a wide range of Yamaha 2-Stroke and 4-Stroke outboard engines from 25HP to 40HP, covering models manufactured between 1993 and 2006.\u003c\/p\u003e\n  \u003cp\u003eIt serves as a direct interchange for Yamaha OEM part numbers 66T-W0078-A0, 66T-W0078-A0-00, 66T-W0078-00-00, and 66T-W0078-01-00, as well as aftermarket cross-references like Sierra 18-3432 and GLM 89890.\u003c\/p\u003e\n  \u003cul\u003e\n    \u003cli\u003eEngineered for direct-fit installation with no modifications required.\u003c\/li\u003e\n    \u003cli\u003eKit includes the essential impeller, gaskets, and key for a complete service.\u003c\/li\u003e\n    \u003cli\u003eRestores cooling system performance to prevent engine overheating and ensure reliability.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\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\u003csection id=\"part-number-matrix\"\u003e\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\u003e66T-W0078-A0\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e66T-W0078-A0-00\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e66T-W0078-00-00\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e66T-W0078-01-00\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-3432\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eGLM\u003c\/td\u003e\n        \u003ctd\u003e89890\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"engine-compatibility\"\u003e\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\u003eFor Yamaha owners, ensure your model and year range match the specifications shown. Note the different OEM part number for the C30 model, which requires an alternative kit.\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\u003eF25\u003c\/td\u003e\n          \u003ctd\u003e25\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e1998–2006\u003c\/td\u003e\n          \u003ctd\u003e66T-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\u003eF30\u003c\/td\u003e\n          \u003ctd\u003e30\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e2001–2006\u003c\/td\u003e\n          \u003ctd\u003e66T-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\u003eF40\u003c\/td\u003e\n          \u003ctd\u003e40\u003c\/td\u003e\n          \u003ctd\u003e4-Stroke\u003c\/td\u003e\n          \u003ctd\u003e1999–2006\u003c\/td\u003e\n          \u003ctd\u003e66T-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\u003eC30\u003c\/td\u003e\n          \u003ctd\u003e30\u003c\/td\u003e\n          \u003ctd\u003e2-Stroke\u003c\/td\u003e\n          \u003ctd\u003e1993–1997\u003c\/td\u003e\n          \u003ctd\u003e61N-W0078-11-00\u003c\/td\u003e\n          \u003ctd\u003eAlternative kit\u003c\/td\u003e\n        \u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"technical-specs\"\u003e\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 replacement\u003c\/dd\u003e\n  \u003c\/dl\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"package-contents\"\u003e\n  \u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cspan style=\"color:#d0021b;\"\u003e1 x\u003c\/span\u003e Impeller\u003c\/li\u003e\n    \u003cli\u003e1 x Water Pump Housing Gasket\u003c\/li\u003e\n    \u003cli\u003e1 x Wear Plate to Gear Case Mounting Gasket\u003c\/li\u003e\n    \u003cli\u003e1 x Wear Plate to Pump Housing Gasket\u003c\/li\u003e\n    \u003cli\u003e\n\u003cspan style=\"color:#d0021b;\"\u003e1 x\u003c\/span\u003e Impeller Key\u003c\/li\u003e\n    \u003cli\u003eAdditional gaskets and O-rings may be included depending on specific kit configuration\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"installation-notes\"\u003e\n  \u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n  \u003col\u003e\n    \u003cli\u003eDisconnect the battery and shift the outboard into the neutral position.\u003c\/li\u003e\n    \u003cli\u003eRemove the lower unit (gearcase) by unbolting it from the engine's midsection.\u003c\/li\u003e\n    \u003cli\u003eUnbolt and remove the water pump housing to access the old impeller.\u003c\/li\u003e\n    \u003cli\u003eNote the rotational direction of the old impeller's vanes before removing it and the impeller key.\u003c\/li\u003e\n    \u003cli\u003eThoroughly clean all mating surfaces, removing any old gasket residue.\u003c\/li\u003e\n    \u003cli\u003eInstall the new impeller key, wear plate, gaskets, and impeller. Bending the new impeller vanes in the correct direction during installation is critical.\u003c\/li\u003e\n    \u003cli\u003eReassemble the pump housing and torque its bolts to the manufacturer's specified value.\u003c\/li\u003e\n    \u003cli\u003eReinstall the lower unit, carefully aligning the driveshaft, shift shaft, and water tube.\u003c\/li\u003e\n    \u003cli\u003eReconnect the battery and test the engine on a water supply, confirming a strong, steady stream from the tell-tale port.\u003c\/li\u003e\n  \u003c\/ol\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"faq\"\u003e\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 fits specific Yamaha 25HP to 40HP models from 1993–2006. Please verify your exact model and year in the 'Engine \u0026amp; Model Compatibility' table and cross-reference your OEM part number with our 'Part Number Matrix' to ensure a perfect match.\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 non-existent water stream from the \"tell-tale\" outlet, engine overheating alarms, and a noticeable drop in performance. A brittle, cracked, or deformed impeller upon inspection confirms failure.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eThe compatibility table lists an \"Alternative kit\" for my C30. What's the difference?\u003c\/summary\u003e\n    \u003cp\u003eThe part number 61N-W0078-11-00 listed for the C30 2-Stroke is a different kit. While this 66T-series kit may have shared components, you must purchase the exact part number specified for your engine to guarantee correct fit and function.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should the water pump impeller be replaced?\u003c\/summary\u003e\n    \u003cp\u003eFor preventative maintenance, we recommend replacing the impeller every 100-200 operating hours or at least once every one to two years, whichever comes first. This interval should be shorter if you frequently operate in sandy, silty, or debris-heavy water.\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\u003c\/section\u003e\n\n\u003csection id=\"safety-info\"\u003e\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 is listed as compatible—do not purchase.\u003c\/li\u003e\n    \u003cli\u003eThis is an aftermarket replacement component, not an Original Equipment Manufacturer (OEM) part.\u003c\/li\u003e\n    \u003cli\u003eProfessional installation is highly recommended for safety, proper function, and engine longevity.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/section\u003e\n\n\u003csection id=\"about-us\"\u003e\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 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, getting you back on the water faster.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eManufacturer-Direct Value\u003c\/strong\u003e — By working directly with manufacturers, we offer 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":50723806445883,"sku":"23KY082","price":22.9,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/Water_Pump_Impeller_Kit_for_Yamaha_25HP-40HP_66T-W0078-A0_-_JLM_MARINE-8289029.jpg?v=1763032262","url":"https:\/\/seasierra.com\/products\/water-pump-impeller-kit-fits-yamaha-25hp-40hp-replaces-66t-w0078-a0-18-3432-89890","provider":"SeaSierra","version":"1.0","type":"link"}