{"product_id":"water-pump-repair-kit-fits-mercury-mariner-30-70hp-replaces-77177a3-46-77177a3","title":"Water Pump Repair Kit – Fits Mercury\/Mariner 30–70HP (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\u003csection\u003e\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis complete \u003cstrong\u003eWater Pump Repair Kit – Fits Mercury\/Mariner 2-Stroke 30–70HP Outboards (Replaces 77177A3, 46-77177A3)\u003c\/strong\u003e is engineered to restore the cooling system on Mercury and Mariner 2-stroke outboard motors ranging from 30 to 70 HP, specifically for models manufactured between 1977 and 1997. The kit provides everything needed for a full water pump rebuild.\u003c\/p\u003e\n\u003cp\u003eIt serves as a direct interchange for Mercury\/Mariner part numbers 77177A3 and 46-77177A3, as well as aftermarket references Sierra 18-3324, GLM 12100, and Mallory 9-48312.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eDesigned for direct replacement of the original factory assembly.\u003c\/li\u003e\n\u003cli\u003eIncludes all essential components: impeller, housings, gaskets, and seals.\u003c\/li\u003e\n\u003cli\u003eCompatible with standard 2-stroke outboard cooling systems.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e\n\u003csection\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\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e77177A3\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\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      \u003ctr\u003e\n        \u003ctd\u003eMallory\u003c\/td\u003e\n        \u003ctd\u003e9-48312\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/section\u003e\n\u003csection\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\u003eThis kit is designed for select Mercury and Mariner outboards. Please check your engine's serial number (SN) against the ranges provided to ensure an exact match.\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\u003e30 HP Jet\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1977–1997\u003c\/td\u003e\n        \u003ctd\u003e77177A3\u003c\/td\u003e\n        \u003ctd\u003eSN. C159200-G589999\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\u003e35 HP\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1977–1997\u003c\/td\u003e\n        \u003ctd\u003e77177A3\u003c\/td\u003e\n        \u003ctd\u003eSN. 6445653-Up\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\u003e40 HP\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1977–1997\u003c\/td\u003e\n        \u003ctd\u003e77177A3\u003c\/td\u003e\n        \u003ctd\u003eSN. 4890103-6445653\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\u003e40 HP (4cyl)\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1977–1997\u003c\/td\u003e\n        \u003ctd\u003e77177A3\u003c\/td\u003e\n        \u003ctd\u003eSN. C159200-Up\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\u003e45 HP\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1977–1997\u003c\/td\u003e\n        \u003ctd\u003e77177A3\u003c\/td\u003e\n        \u003ctd\u003eSN. 5531630-Up\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\u003e50 HP (4cyl)\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1977–1997\u003c\/td\u003e\n        \u003ctd\u003e77177A3\u003c\/td\u003e\n        \u003ctd\u003eSN. 4962056-Up\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\u003e50 HP (3cyl)\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1977–1997\u003c\/td\u003e\n        \u003ctd\u003e77177A3\u003c\/td\u003e\n        \u003ctd\u003eSN. 6428681-D000749\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\u003e60 HP\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1977–1997\u003c\/td\u003e\n        \u003ctd\u003e77177A3\u003c\/td\u003e\n        \u003ctd\u003eSN. 6428681-D000749\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\u003e65 HP (3cyl)\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1977–1997\u003c\/td\u003e\n        \u003ctd\u003e77177A3\u003c\/td\u003e\n        \u003ctd\u003eSN. 4382057-4571651\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\u003e70 HP\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1977–1997\u003c\/td\u003e\n        \u003ctd\u003e77177A3\u003c\/td\u003e\n        \u003ctd\u003eSN. 4977157-B110053\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n\u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eProduct Type\u003c\/dt\u003e\n\u003cdd\u003eComplete Water Pump Repair Kit\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect replacement for original equipment\u003c\/dd\u003e\n  \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003eCompatible with 2-stroke outboard cooling systems\u003c\/dd\u003e\n\u003c\/dl\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n\u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e1 x Upper Pump Housing (18-3118)\u003c\/li\u003e\n  \u003cli\u003e1 x Lower Pump Housing\/Water Pump Base (18-3424)\u003c\/li\u003e\n  \u003cli\u003e1 x Impeller (18-3007)\u003c\/li\u003e\n  \u003cli\u003e1 x Face Plate (18-3107)\u003c\/li\u003e\n  \u003cli\u003e1 x Drain Gasket (18-2945)\u003c\/li\u003e\n  \u003cli\u003e1 x Lower Water Pump Base to Face Plate Gasket (18-2823)\u003c\/li\u003e\n  \u003cli\u003e1 x Upper Face Plate to Body Gasket (18-2824)\u003c\/li\u003e\n  \u003cli\u003e1 x Water Pump Base Gasket (18-2825)\u003c\/li\u003e\n  \u003cli\u003e1 x Water Pump Base Gasket (18-2841)\u003c\/li\u003e\n  \u003cli\u003e1 x Drain Plug (18-2948)\u003c\/li\u003e\n  \u003cli\u003e1 x O-Ring (18-7155)\u003c\/li\u003e\n  \u003cli\u003e1 x O-Ring (18-7174)\u003c\/li\u003e\n  \u003cli\u003e1 x O-Ring (18-7115)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/section\u003e\n\u003csection\u003e\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect the battery and shift linkage.\u003c\/li\u003e\n  \u003cli\u003eUnbolt and carefully remove the lower unit (gearcase) from the outboard leg.\u003c\/li\u003e\n  \u003cli\u003eRemove the old water pump housing bolts and lift the housing assembly off the driveshaft.\u003c\/li\u003e\n  \u003cli\u003eSlide the old impeller off the driveshaft, taking note of the drive key's position. Remove old gaskets and the wear plate.\u003c\/li\u003e\n  \u003cli\u003eThoroughly clean all mating surfaces, ensuring they are free of old gasket material and corrosion.\u003c\/li\u003e\n  \u003cli\u003eInstall the new gaskets, wear plate, and drive key onto the driveshaft.\u003c\/li\u003e\n  \u003cli\u003eSlide the new impeller onto the driveshaft. Rotate the driveshaft clockwise while pushing down to correctly seat the impeller vanes inside the new housing.\u003c\/li\u003e\n  \u003cli\u003eInstall the new housing and tighten bolts to the manufacturer's specified torque in a crisscross pattern.\u003c\/li\u003e\n  \u003cli\u003eApply a light coat of marine grease to the driveshaft splines and reinstall the lower unit, making sure the water tube, driveshaft, and shift shaft align correctly.\u003c\/li\u003e\n  \u003cli\u003eReconnect the shift linkage and battery. Start the engine using a water supply (flushing attachment or in water) and confirm a steady stream from the cooling system's tell-tale outlet.\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003c\/section\u003e\n\u003csection\u003e\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 non-existent stream of water from the \"tell-tale\" outlet, engine overheating alerts, or a melted\/deformed pump housing upon inspection. Reduced engine performance at high RPMs can also indicate poor cooling.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is the recommended replacement interval for an impeller?\u003c\/summary\u003e\n  \u003cp\u003eFor optimal reliability, most manufacturers recommend inspecting the impeller annually and replacing it every 1-2 years or every 100-200 hours of operation, depending on usage conditions (e.g., saltwater vs. freshwater).\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eMy engine model is listed, but the serial number is different. Will this kit fit?\u003c\/summary\u003e\n  \u003cp\u003eThe serial number (SN) ranges are critical for ensuring correct fitment, as manufacturers often make mid-year design changes. We strongly recommend purchasing only if your engine's serial number falls within the specified ranges. If in doubt, contact us with your full engine details before ordering.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs this a complete kit, or do I need to buy other parts?\u003c\/summary\u003e\n  \u003cp\u003eThis is a complete repair kit containing all the necessary components for a standard water pump rebuild, including the impeller, housings, gaskets, and O-rings as listed in the \"What’s in the Box\" section. No other parts should be required for a standard replacement.\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\u003csection\u003e\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\u003c\/section\u003e\n\u003csection\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 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\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723964748091,"sku":"LY-PZHR-Y7U8","price":39.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/LY-PZHR-Y7U8.png?v=1763038558","url":"https:\/\/seasierra.com\/products\/water-pump-repair-kit-fits-mercury-mariner-30-70hp-replaces-77177a3-46-77177a3","provider":"SeaSierra","version":"1.0","type":"link"}