{"product_id":"outboard-maintenance-kit-fits-mercury-mariner-4-6-hp-4-stroke-replaces-8m0120836-3gr-87500-0","title":"Outboard Maintenance Kit – Fits Mercury\/Mariner 4-6 HP 4-Stroke (Replaces 8M0120836, 3GR-87500-0)","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\u003eOutboard Maintenance Kit – Fits Mercury\/Mariner 4-6 HP 4-Stroke (Replaces 8M0120836, 3GR-87500-0)\u003c\/strong\u003e contains essential components for performing routine 300-hour service on Mercury and Mariner 4HP, 5HP, and 6HP 4-Stroke outboard motors (serial numbers 0R411838 and above).\u003c\/p\u003e\n\u003cp\u003eIt serves as a direct aftermarket replacement for Mercury\/Mariner part numbers 8M0120836 and 3GR-87500-0.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eComplete kit for scheduled 300-hour outboard service intervals.\u003c\/li\u003e\n\u003cli\u003eIncludes engine-specific replacement components for fuel and cooling systems.\u003c\/li\u003e\n\u003cli\u003eEngineered for gasoline-fueled 4-stroke marine engines.\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\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e8M0120836\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e3GR-87500-0\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\u003e\u003cb\u003eFor Mercury\/Mariner Owners:\u003c\/b\u003e This kit is designed for specific 4-Stroke models from 4HP to 6HP with serial numbers 0R411838 and newer. Please verify your serial number before ordering.\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\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\u003e4HP\u003c\/td\u003e\n        \u003ctd\u003e4\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e8M0120836\u003c\/td\u003e\n        \u003ctd\u003eSerial numbers 0R411838 and above\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e5HP\u003c\/td\u003e\n        \u003ctd\u003e5\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e8M0120836\u003c\/td\u003e\n        \u003ctd\u003eSerial numbers 0R411838 and above\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e6HP\u003c\/td\u003e\n        \u003ctd\u003e6\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e8M0120836\u003c\/td\u003e\n        \u003ctd\u003eSerial numbers 0R411838 and above\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\u003eOutboard Maintenance Service Kit\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eEngine-specific replacement components\u003c\/dd\u003e\n  \u003cdt\u003eFuel Type\u003c\/dt\u003e\n\u003cdd\u003eGasoline\u003c\/dd\u003e\n  \u003cdt\u003eHousing Material\u003c\/dt\u003e\n\u003cdd\u003eMultiple materials (Neoprene impeller)\u003c\/dd\u003e\n  \u003cdt\u003eWeight\u003c\/dt\u003e\n\u003cdd\u003e0.045 kg (0.1 lb)\u003c\/dd\u003e\n  \u003cdt\u003eOther Technical Attributes\u003c\/dt\u003e\n\u003cdd\u003e300-Hour service interval maintenance kit\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 (47-16154-3)\u003c\/li\u003e\n\u003cli\u003e1 x Cotter Pin (8150264)\u003c\/li\u003e\n\u003cli\u003e1 x Pin Key (28-16155)\u003c\/li\u003e\n\u003cli\u003e1 x Thermostat (804540)\u003c\/li\u003e\n\u003cli\u003e1 x Thermostat Gasket (27-8M0214960)\u003c\/li\u003e\n\u003cli\u003e1 x O-Ring (25-16131)\u003c\/li\u003e\n\u003cli\u003e1 x Oil Seal (16130\/26-16130)\u003c\/li\u003e\n\u003cli\u003e1 x Fuel Filter (35-8M0157133)\u003c\/li\u003e\n\u003cli\u003e1 x Gaskets (8035161)\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"color:#d0021b;\"\u003e2 x\u003c\/span\u003e Drain Gasket (27-95220)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n\u003cli\u003eDisconnect the battery and fuel lines for safety.\u003c\/li\u003e\n\u003cli\u003ePosition a drain pan and remove the drain plugs to empty the engine oil and gearcase lubricant.\u003c\/li\u003e\n\u003cli\u003eDisassemble the lower unit to access and replace the water pump impeller, seals, and key.\u003c\/li\u003e\n\u003cli\u003eRemove the thermostat cover, then install the new thermostat and gasket.\u003c\/li\u003e\n\u003cli\u003eLocate and replace the existing fuel filter with the new one.\u003c\/li\u003e\n\u003cli\u003eInstall new drain plug gaskets, tighten the plugs to the manufacturer's torque specification, and refill the engine and gearcase with the correct grade of oil.\u003c\/li\u003e\n\u003cli\u003eReconnect fuel lines and the battery.\u003c\/li\u003e\n\u003cli\u003eBefore navigating, run the engine and carefully check for any fuel, oil, or water leaks.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\u003csummary\u003eHow do I know if this kit fits my engine?\u003c\/summary\u003e\u003cp\u003eThis kit is specifically for Mercury and Mariner 4HP, 5HP, and 6HP 4-stroke outboard motors with serial numbers 0R411838 and newer. Always check your engine's serial number against the compatibility table before purchasing.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat is the recommended service interval for this kit?\u003c\/summary\u003e\u003cp\u003eThis is a 300-hour service kit. It is designed to replace key components as part of your engine's scheduled maintenance routine every 300 hours of operation or as specified by the manufacturer.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat are signs that my outboard needs this maintenance?\u003c\/summary\u003e\u003cp\u003eCommon indicators include engine overheating (often due to a worn impeller), poor fuel flow (clogged filter), or if it has been 300 operating hours since the last major service. Preventative maintenance is key to avoiding failure.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eAre special tools required for installation?\u003c\/summary\u003e\u003cp\u003eStandard mechanic's tools are required. A torque wrench is highly recommended for tightening drain plugs and other components to manufacturer specifications to prevent leaks and damage.\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 \u0026amp; 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\u003cb\u003ePro-Grade Standards\u003c\/b\u003e — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eFast Global Fulfillment\u003c\/b\u003e — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eManufacturer-Direct Value\u003c\/b\u003e — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723969401147,"sku":"23KM771R","price":42.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/23KM771R.png?v=1763038765","url":"https:\/\/seasierra.com\/products\/outboard-maintenance-kit-fits-mercury-mariner-4-6-hp-4-stroke-replaces-8m0120836-3gr-87500-0","provider":"SeaSierra","version":"1.0","type":"link"}