{"product_id":"water-pump-impeller-kit-fits-mercury-mariner-3-5-9-8-hp-replaces-47-89980t1-89980q1","title":"Water Pump Impeller Kit – Fits Mercury\/Mariner 3.5-9.8 HP (Replaces 47-89980T1, 89980Q1)","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\u003c\/strong\u003e is designed for Mercury\/Mariner 3.5–9.8 HP 1-cylinder 2-Stroke outboards manufactured between 1979 and 1986. It is specifically engineered for models requiring an impeller with a 0.438-inch inner diameter, ensuring reliable cooling performance and engine protection.\u003c\/p\u003e\n\u003cp\u003eIt serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 47-89980T1, Mercury 89980Q1, Mercury\/Mariner 47-89980Q1, and Sierra 18-3446.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eEngineered as a direct-fit replacement for straightforward installation.\u003c\/li\u003e\n\u003cli\u003eThe impeller is constructed from a durable neoprene\/rubber compound for longevity.\u003c\/li\u003e\n\u003cli\u003eKit includes essential wear plates, O-rings, and seals 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.\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\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e47-89980T1\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e89980Q1\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e47-89980Q1\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-3446\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\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\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003eOutboard\u003c\/td\u003e\n        \u003ctd\u003e9.8\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1979–1985\u003c\/td\u003e\n        \u003ctd\u003e47-89980T1\/89980Q1\u003c\/td\u003e\n        \u003ctd\u003e0.438\" Imp. ID\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003eOutboard\u003c\/td\u003e\n        \u003ctd\u003e7.5\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1979–1986\u003c\/td\u003e\n        \u003ctd\u003e47-89980T1\/89980Q1\u003c\/td\u003e\n        \u003ctd\u003e0.438\" Imp. ID\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003eOutboard\u003c\/td\u003e\n        \u003ctd\u003e4.5\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1980–1985\u003c\/td\u003e\n        \u003ctd\u003e47-89980T1\/89980Q1\u003c\/td\u003e\n        \u003ctd\u003e1-Cyl, 0.438\" Imp. ID\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003eOutboard\u003c\/td\u003e\n        \u003ctd\u003e4\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1982–1986\u003c\/td\u003e\n        \u003ctd\u003e47-89980T1\/89980Q1\u003c\/td\u003e\n        \u003ctd\u003e1-Cyl, 0.438\" Imp. ID\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 replacement\u003c\/dd\u003e\n  \u003cdt\u003eImpeller Material\u003c\/dt\u003e\n\u003cdd\u003eNeoprene\/rubber compound\u003c\/dd\u003e\n  \u003cdt\u003eImpeller ID\u003c\/dt\u003e\n\u003cdd\u003e0.438\" (11.13 mm)\u003c\/dd\u003e\n  \u003cdt\u003eImpeller Hub Width\/Height\u003c\/dt\u003e\n\u003cdd\u003e14.4 mm\u003c\/dd\u003e\n  \u003cdt\u003eNumber of Blades\u003c\/dt\u003e\n\u003cdd\u003e6\u003c\/dd\u003e\n  \u003cdt\u003eOperating Temperature\u003c\/dt\u003e\n\u003cdd\u003eUp to 105°C (221°F)\u003c\/dd\u003e\n  \u003cdt\u003eWarranty\u003c\/dt\u003e\n\u003cdd\u003e1 Year (varies by seller)\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 Sleeve (700-12963)\u003c\/li\u003e\n  \u003cli\u003e1 x Impeller (700-89800)\u003c\/li\u003e\n  \u003cli\u003e1 x Wear Plate (700-12560)\u003c\/li\u003e\n  \u003cli\u003e1 x O-Ring (700-81230)\u003c\/li\u003e\n  \u003cli\u003e1 x O-Ring (700-81090)\u003c\/li\u003e\n  \u003cli\u003e1 x Seal (700-85651)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect the spark plug leads and battery cables for safety.\u003c\/li\u003e\n  \u003cli\u003ePosition a drain pan and remove the gearcase drain and vent screws to drain the lower unit oil.\u003c\/li\u003e\n  \u003cli\u003eRemove the bolts securing the lower unit (gearcase) to the engine midsection.\u003c\/li\u003e\n  \u003cli\u003eCarefully lower the gearcase to access the water pump housing.\u003c\/li\u003e\n  \u003cli\u003eRemove the water pump housing bolts and slide the housing up to expose the old impeller.\u003c\/li\u003e\n  \u003cli\u003eRemove the old impeller, key, gaskets, and wear plate, noting their orientation.\u003c\/li\u003e\n  \u003cli\u003eClean all mating surfaces thoroughly, removing any old gasket material or debris.\u003c\/li\u003e\n  \u003cli\u003eInstall the new wear plate, gaskets, and seals provided in the kit.\u003c\/li\u003e\n  \u003cli\u003eSlide the new impeller onto the driveshaft. Lubricate the housing interior and turn the driveshaft clockwise to seat the blades correctly.\u003c\/li\u003e\n  \u003cli\u003eReinstall the water pump housing, ensuring all seals are correctly positioned, and tighten bolts to the manufacturer's specified torque.\u003c\/li\u003e\n  \u003cli\u003eReattach the lower unit to the engine, refilling it with fresh gear oil before tightening the screws.\u003c\/li\u003e\n  \u003cli\u003eReconnect the battery and spark plugs. Start the engine in water and verify 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\u003csummary\u003eHow do I confirm this kit fits my specific engine?\u003c\/summary\u003e\u003cp\u003eVerify that your engine is a Mercury\/Mariner 3.5–9.8 HP 2-stroke model from the years listed in the compatibility table. A critical check is to confirm your old impeller has an inner diameter of 0.438 inches, as some models used different sizes.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat are the signs of a bad impeller?\u003c\/summary\u003e\u003cp\u003eCommon symptoms include a weak or non-existent water stream from the \"tell-tale\" outlet, engine overheating alerts or steam from the exhaust, and a melted or warped water pump housing. Failure to replace a worn impeller can lead to severe engine damage.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eHow often should I replace my water pump impeller?\u003c\/summary\u003e\u003cp\u003eAs a best practice, impellers should be replaced every 1-2 years or every 100-200 hours of operation, whichever comes first. For boats used in saltwater or sandy\/silty conditions, annual replacement is strongly recommended to prevent premature failure.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhy does the old impeller look fine but the engine still overheats?\u003c\/summary\u003e\u003cp\u003eAn impeller can lose its flexibility and \"set\" over time, even if it appears visually intact. This prevents the blades from flexing properly against the pump housing, reducing pumping efficiency. Material fatigue is not always visible to the naked eye.\u003c\/p\u003e\n\u003cdetails\u003e\u003csummary\u003eIs anything else needed for installation?\u003c\/summary\u003e\u003cp\u003eThis kit contains the core components. However, you will also need marine-grade grease for lubrication, gasket sealant (optional, but recommended by some mechanics), and fresh lower unit gear oil for refilling the gearcase after service.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\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\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eShipping speed \u0026amp; cost\u003c\/summary\u003e\u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWarranty \u0026amp; returns\u003c\/summary\u003e\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 in original condition). See our policy page or reach out for instructions.\u003c\/p\u003e\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\/details\u003e\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723963666747,"sku":"6Y-JF9V-8O9J","price":30.07,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/6Y-JF9V-8O9J.png?v=1763038507","url":"https:\/\/seasierra.com\/products\/water-pump-impeller-kit-fits-mercury-mariner-3-5-9-8-hp-replaces-47-89980t1-89980q1","provider":"SeaSierra","version":"1.0","type":"link"}