{"product_id":"26-77066a1-gearcase-seal-kit-for-mercury-mariner-force-jlm-marine","title":"26-77066A1 Gearcase Seal Kit for Mercury Mariner Force | JLM Marine","description":"\u003ch2\u003eGearcase Seal Kit – Fits Mercury, Mariner, and Force 3.9–9.8 HP Outboards (1975–1986)\u003c\/h2\u003e\n\n\u003cp\u003eThis \u003cstrong\u003egearcase seal kit\u003c\/strong\u003e is designed to fit \u003cstrong\u003e3.9–9.8 HP Mercury, Mariner, and Force outboard lower units\u003c\/strong\u003e manufactured from \u003cstrong\u003e1975 to 1986\u003c\/strong\u003e. It provides a complete sealing solution for your lower unit, ensuring reliable protection against water intrusion and gear oil leaks.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDirect replacements:\u003c\/strong\u003e Mercury 26-77066A1, Sierra 18-2628. This kit is engineered to meet OEM specifications and delivers dependable performance for vintage outboard motors.\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eComplete seal kit with all necessary components for lower unit maintenance\u003c\/li\u003e\n  \u003cli\u003eCompatible with multiple Mercury, Mariner, and Force models from 1975–1986\u003c\/li\u003e\n  \u003cli\u003eAftermarket replacement built to OEM standards\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Cross-Reference\u003c\/h2\u003e\n\n\u003cp\u003eUse this table to confirm equivalent part numbers across OEM and aftermarket brands.\u003c\/p\u003e\n\n\u003ctable border=\"1\" cellpadding=\"8\" cellspacing=\"0\"\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\u003e26-77066A1\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eSierra\u003c\/td\u003e\n      \u003ctd\u003e18-2628\u003c\/td\u003e\n    \u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eCompatible Engine Models\u003c\/h2\u003e\n\n\u003cp\u003eConfirm your engine model\/year in the table below. For Mercury owners, here's a guide to help you identify your engine's serial\/model: \u003ca href=\"https:\/\/jlmmarine.com\/blogs\/serial-number-guide\/mercury-outboard-serial-number-guide\" rel=\"nofollow noopener\" target=\"_blank\"\u003eMercury Serial Number Guide\u003c\/a\u003e. You can also review exploded diagrams to verify part numbers: \u003ca href=\"https:\/\/jlmmarine.com\/blogs\/diagrams\/mercury-parts-catalog\" rel=\"nofollow noopener\" target=\"_blank\"\u003eMercury Parts Diagrams \u0026amp; Catalog\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003cdiv style=\"overflow-x:auto;\"\u003e\n  \u003ctable border=\"1\" cellpadding=\"8\" cellspacing=\"0\"\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\u003eYears\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\u003eOutboard\u003c\/td\u003e\n        \u003ctd\u003e3.9, 4, 4.5, 6, 7.5, 8, 9.8\u003c\/td\u003e\n        \u003ctd\u003e1975–1986\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMariner\u003c\/td\u003e\n        \u003ctd\u003eOutboard\u003c\/td\u003e\n        \u003ctd\u003e3.9, 4, 4.5, 6, 7.5, 8, 9.8\u003c\/td\u003e\n        \u003ctd\u003e1975–1986\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eForce\u003c\/td\u003e\n        \u003ctd\u003eOutboard\u003c\/td\u003e\n        \u003ctd\u003e3.9, 4, 4.5, 6, 7.5, 8, 9.8\u003c\/td\u003e\n        \u003ctd\u003e1975–1986\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\n\u003ctable border=\"1\" cellpadding=\"8\" cellspacing=\"0\"\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n      \u003cth\u003eSpecification\u003c\/th\u003e\n      \u003cth\u003eValue\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eOEM Part Number\u003c\/td\u003e\n      \u003ctd\u003e26-77066A1\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eAftermarket Part Number\u003c\/td\u003e\n      \u003ctd\u003e18-2628 (Sierra)\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eApplication\u003c\/td\u003e\n      \u003ctd\u003eGearcase\/Lower Unit Seals\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eCompatible HP Range\u003c\/td\u003e\n      \u003ctd\u003e3.9–9.8 HP\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eCompatible Years\u003c\/td\u003e\n      \u003ctd\u003e1975–1986\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eType\u003c\/td\u003e\n      \u003ctd\u003eSeal Kit\u003c\/td\u003e\n    \u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003ePackage Contents\u003c\/h2\u003e\n\n\u003cp\u003eThis gearcase seal kit includes:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\u003cspan style=\"color:red;\"\u003e1× Complete Gearcase Seal Kit (The package contains all the parts shown in the product image.)\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Guide\u003c\/h2\u003e\n\n\u003col\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePreparation:\u003c\/strong\u003e Disconnect the spark plug wire and drain all gear oil from the lower unit. Clean the work area thoroughly.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRemove Lower Unit:\u003c\/strong\u003e Detach the lower unit from the mid-section by removing the mounting bolts and shift linkage.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDisassemble Gearcase:\u003c\/strong\u003e Remove the propeller, propeller shaft, and drive shaft. Take care to note the orientation of components for reassembly.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRemove Old Seals:\u003c\/strong\u003e Carefully pry out old seals using a seal puller or flat-blade screwdriver. Avoid damaging the seal housing surfaces.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eClean Housing Surfaces:\u003c\/strong\u003e Thoroughly clean all seal housing areas with solvent and a lint-free cloth. Inspect for wear, corrosion, or damage.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInstall New Seals:\u003c\/strong\u003e Lightly lubricate new seals with gear oil. Press seals into place squarely using a seal driver or socket of appropriate diameter.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReassemble Gearcase:\u003c\/strong\u003e Reinstall drive shaft, propeller shaft, and related components in reverse order of disassembly. Ensure all components are properly aligned.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReattach Lower Unit:\u003c\/strong\u003e Mate the lower unit to the mid-section, reconnect shift linkage, and torque mounting bolts to manufacturer specifications.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRefill Gear Oil:\u003c\/strong\u003e Fill the lower unit with the recommended gear oil through the lower fill hole until oil appears at the upper vent hole. Install and tighten both plugs.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFinal Check:\u003c\/strong\u003e Reinstall the propeller, reconnect the spark plug wire, and test-run the engine in a test tank or on the water. Check for leaks and proper shifting.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: How do I confirm this seal kit fits my engine?\u003c\/strong\u003e\u003cbr\u003e\nA: Cross-reference your engine's HP rating (3.9–9.8 HP) and manufacturing year (1975–1986) with the compatibility table above. Verify your original part number matches Mercury 26-77066A1 or Sierra 18-2628.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What are the signs that my gearcase seals need replacement?\u003c\/strong\u003e\u003cbr\u003e\nA: Common symptoms include visible gear oil leaks around the lower unit, water contamination in the gear oil (milky appearance), difficulty shifting gears, or unusual noise from the lower unit.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: How often should I replace the gearcase seals?\u003c\/strong\u003e\u003cbr\u003e\nA: Replace seals whenever you notice leaks, water intrusion, or during major lower unit service (typically every 3–5 years or as needed).\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Can I install this seal kit myself?\u003c\/strong\u003e\u003cbr\u003e\nA: Installation requires disassembly of the lower unit and familiarity with outboard service procedures. If you have mechanical experience and the proper tools, DIY installation is possible. Otherwise, professional installation is recommended.\u003c\/p\u003e\n\n\u003ch2\u003eImportant Notes\u003c\/h2\u003e\n\n\u003cul\u003e\n  \u003cli\u003eVerify that the product images and specifications match your original part before purchasing.\u003c\/li\u003e\n  \u003cli\u003eThis product is an aftermarket replacement part and is not an OEM component.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended to ensure safety and optimal performance.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"JLM Marine","offers":[{"title":"Default Title","offer_id":51981022036281,"sku":"24MSK713","price":40.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0885\/0433\/6697\/files\/12_61d89890-0eec-42b6-8ff4-6e2eeb7f8820.jpg?v=1772414722","url":"https:\/\/jlmmarine.com\/es\/products\/26-77066a1-gearcase-seal-kit-for-mercury-mariner-force-jlm-marine","provider":"JLM Marine Boat Parts Limited","version":"1.0","type":"link"}