{"product_id":"water-pump-impeller-kit-fits-mercury-mariner-30-70-hp-replaces-77177a3-46-77177a3","title":"Water Pump Impeller Kit – Fits Mercury\/Mariner 30-70 HP (Replaces 77177A3, 46-77177A3)","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 and Mariner 30–70 HP 2-stroke outboard engines manufactured between 1977 and 1997. It ensures your engine's cooling system functions efficiently, preventing overheating and potential damage.\u003c\/p\u003e\n\u003cp\u003eThe kit serves as a direct replacement for Mercury part numbers 77177A3 and 46-77177A3, as well as Sierra 18-3324 and GLM 12100, providing a comprehensive solution for your maintenance needs.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eEngineered as a direct-fit replacement for specified models.\u003c\/li\u003e\n\u003cli\u003eInstallation can be performed with standard marine service tools.\u003c\/li\u003e\n\u003cli\u003eIncludes all essential components for a complete water pump rebuild.\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 brands.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Cross-Reference\"\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\u003e77177A3\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\u003c\/td\u003e\n        \u003ctd\u003e46-77177A3\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-3324\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eGLM\u003c\/td\u003e\n        \u003ctd\u003e12100\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 and year in the table below to ensure accurate fitment.\u003c\/p\u003e\n\u003cp\u003eThis kit is compatible with 2-stroke outboard models from Mercury and Mariner.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Engine 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\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e30 HP\u003c\/td\u003e\n\u003ctd\u003e30\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e35 HP\u003c\/td\u003e\n\u003ctd\u003e35\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e40 HP\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e45 HP\u003c\/td\u003e\n\u003ctd\u003e45\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e50 HP\u003c\/td\u003e\n\u003ctd\u003e50\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e60 HP\u003c\/td\u003e\n\u003ctd\u003e60\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e65 HP\u003c\/td\u003e\n\u003ctd\u003e65\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMercury\u003c\/td\u003e\n\u003ctd\u003e70 HP\u003c\/td\u003e\n\u003ctd\u003e70\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMariner\u003c\/td\u003e\n\u003ctd\u003e30 HP\u003c\/td\u003e\n\u003ctd\u003e30\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMariner\u003c\/td\u003e\n\u003ctd\u003e35 HP\u003c\/td\u003e\n\u003ctd\u003e35\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMariner\u003c\/td\u003e\n\u003ctd\u003e40 HP\u003c\/td\u003e\n\u003ctd\u003e40\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-7717A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMariner\u003c\/td\u003e\n\u003ctd\u003e45 HP\u003c\/td\u003e\n\u003ctd\u003e45\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMariner\u003c\/td\u003e\n\u003ctd\u003e50 HP\u003c\/td\u003e\n\u003ctd\u003e50\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMariner\u003c\/td\u003e\n\u003ctd\u003e60 HP\u003c\/td\u003e\n\u003ctd\u003e60\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMariner\u003c\/td\u003e\n\u003ctd\u003e65 HP\u003c\/td\u003e\n\u003ctd\u003e65\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd\u003eMariner\u003c\/td\u003e\n\u003ctd\u003e70 HP\u003c\/td\u003e\n\u003ctd\u003e70\u003c\/td\u003e\n\u003ctd\u003e2-Stroke\u003c\/td\u003e\n\u003ctd\u003e1977–1997\u003c\/td\u003e\n\u003ctd\u003e77177A3\/46-77177A3\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\u003eHousing Material\u003c\/dt\u003e\n\u003cdd\u003eRubber (Impeller), Metal (Housing)\u003c\/dd\u003e\n  \u003cdt\u003eHousing Color\u003c\/dt\u003e\n\u003cdd\u003eBlack\u003c\/dd\u003e\n  \u003cdt\u003eWarranty\u003c\/dt\u003e\n\u003cdd\u003eVaries by manufacturer\u003c\/dd\u003e\n  \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eIncludes complete water pump rebuild kit with housing\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 Impeller\u003c\/li\u003e\n  \u003cli\u003e1 x Drive Key\u003c\/li\u003e\n  \u003cli\u003e1 x Impeller Plate\u003c\/li\u003e\n  \u003cli\u003e1 x Gaskets Set\u003c\/li\u003e\n  \u003cli\u003e1 x Water Pump Housing\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect the battery and shift the outboard into neutral.\u003c\/li\u003e\n  \u003cli\u003eDrain the gearcase lubricant from the lower unit.\u003c\/li\u003e\n  \u003cli\u003eRemove the mounting bolts securing the lower unit (gearcase) to the engine.\u003c\/li\u003e\n  \u003cli\u003eCarefully lower and separate the gearcase from the drive shaft housing.\u003c\/li\u003e\n  \u003cli\u003eUnbolt and remove the old water pump housing assembly.\u003c\/li\u003e\n  \u003cli\u003eClean the mounting surfaces and inspect the driveshaft for wear or damage.\u003c\/li\u003e\n  \u003cli\u003eAssemble the new impeller, key, plate, gaskets, and housing from the kit. Lubricate the impeller and housing interior with a suitable marine grease.\u003c\/li\u003e\n  \u003cli\u003eInstall the new water pump assembly onto the driveshaft and bolt it into place.\u003c\/li\u003e\n  \u003cli\u003eRealign the driveshaft, water tube, and shift shaft, then reinstall the lower unit.\u003c\/li\u003e\n  \u003cli\u003eRefill the gearcase with new lubricant according to manufacturer specifications.\u003c\/li\u003e\n  \u003cli\u003eReconnect the battery and test the engine in the water, confirming 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\u003eHow do I know if my water pump is failing?\u003c\/summary\u003e\n  \u003cp\u003eCommon signs include a weak or nonexistent water stream from the \"tell-tale\" outlet, engine overheating alarms, or a noticeable decrease in engine performance. A visual inspection may reveal a melted housing or impeller blades that are cracked, brittle, or have taken a set.\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, it is recommended to inspect the impeller annually and replace it every 2-3 years or every 200-300 hours of operation, whichever comes first. This interval can be shorter in saltwater or silty\/sandy conditions.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this kit difficult to install?\u003c\/summary\u003e\n  \u003cp\u003eInstallation is straightforward for those with mechanical experience and the correct tools. It involves removing the lower unit of the outboard. If you are not comfortable with this process, professional installation is recommended.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhy does this kit include a new housing?\u003c\/summary\u003e\n  \u003cp\u003eAn old or scored housing can reduce pumping efficiency and cause premature wear on the new impeller. Replacing the housing along with the impeller ensures a tight seal and optimal cooling performance, extending the life of the repair.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eMy engine model is listed, but my part looks different. What should I do?\u003c\/summary\u003e\n  \u003cp\u003eDo not install the part. Manufacturers sometimes make mid-year changes. Always compare the new parts in the kit to your old parts before installation. If they do not match, contact us for assistance.\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\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 and 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\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":50723964715323,"sku":"21KM009OC","price":27.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/21KM009OC.png?v=1763038556","url":"https:\/\/seasierra.com\/products\/water-pump-impeller-kit-fits-mercury-mariner-30-70-hp-replaces-77177a3-46-77177a3","provider":"SeaSierra","version":"1.0","type":"link"}