{"product_id":"lower-unit-gasket-seal-kit-fits-mercury-mariner-25-30hp-replaces-27-8m0089639-95220a1","title":"Lower Unit Gasket Seal Kit – Fits Mercury\/Mariner 25-30HP (Replaces 27-8M0089639, 95220A1)","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\u003eLower Unit Gasket Seal Kit\u003c\/strong\u003e is designed for Mercury\/Mariner 2-stroke outboard engines, specifically covering 25 HP, 30 HP, and 25 Jet models manufactured between 1984 and 1991. It provides all the necessary components to reseal the gearcase, preventing water intrusion and oil leaks.\u003c\/p\u003e\n\u003cp\u003eIt serves as a direct aftermarket replacement for Mercury part numbers 27-8M0089639, 95220A1, 804908A01, and 27-8M0089636, and is equivalent to Yamaha references such as 689-W0001-22-00.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eInstalls in the lower unit (gear case) to restore watertight integrity.\u003c\/li\u003e\n\u003cli\u003eIncludes a complete set of gaskets, seals, and O-rings for a full service.\u003c\/li\u003e\n\u003cli\u003eEssential for routine lower unit maintenance, repairs, or rebuilds.\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\u003e27-8M0089639\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e95220A1\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e804908A01\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e27-8M0089636\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e41899M\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e27-41899M\u003c\/td\u003e\n      \u003c\/tr\u003e\n       \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e689-W0001-22-00 (Cross-Reference)\u003c\/td\u003e\n      \u003c\/tr\u003e\n       \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e689-W0001-21-00 (Cross-Reference)\u003c\/td\u003e\n      \u003c\/tr\u003e\n       \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e689-W0001-C1-00 (Cross-Reference)\u003c\/td\u003e\n      \u003c\/tr\u003e\n       \u003ctr\u003e\n        \u003ctd\u003eYamaha\u003c\/td\u003e\n        \u003ctd\u003e689-W0001-C2-00 (Cross-Reference)\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\u003eFor Mercury\/Mariner owners, this kit fits a range of 2-cylinder, 430cc models from the mid-1980s to the early 1990s. Please verify your specific model code and year against the list.\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\u003e25\/25 JET\/30HP (2 CYL\/430CC)\u003c\/td\u003e\n        \u003ctd\u003e25–30\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1984–1991\u003c\/td\u003e\n        \u003ctd\u003e27-8M0089639, 95220A1\u003c\/td\u003e\n        \u003ctd\u003eInternational models\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e25 Jet\u003c\/td\u003e\n        \u003ctd\u003e25 Jet\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1984–1991\u003c\/td\u003e\n        \u003ctd\u003e27-8M0089639, 95220A1\u003c\/td\u003e\n        \u003ctd\u003e2 cylinder\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e25ELK, 25ESK, 25LK, 25SK\u003c\/td\u003e\n        \u003ctd\u003e25\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1985\u003c\/td\u003e\n        \u003ctd\u003e41899M, 27-41899M\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e30ELN, 30ESN\u003c\/td\u003e\n        \u003ctd\u003e30\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1984\u003c\/td\u003e\n        \u003ctd\u003e41899M, 27-41899M\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e30ELK, 30ESK\u003c\/td\u003e\n        \u003ctd\u003e30\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1985\u003c\/td\u003e\n        \u003ctd\u003e41899M, 27-41899M\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e25ELJ, 25ESJ, 25LJ, 25SJ\u003c\/td\u003e\n        \u003ctd\u003e25\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1986\u003c\/td\u003e\n        \u003ctd\u003e41899M, 27-41899M\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e30ELJ, 30ESJ\u003c\/td\u003e\n        \u003ctd\u003e30\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1986\u003c\/td\u003e\n        \u003ctd\u003e41899M, 27-41899M\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003e25ELH, 25ESH, 25LH, 25SH\u003c\/td\u003e\n        \u003ctd\u003e25\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1987\u003c\/td\u003e\n        \u003ctd\u003e41899M, 27-41899M\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003eCV30ELF\u003c\/td\u003e\n        \u003ctd\u003e30\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1989\u003c\/td\u003e\n        \u003ctd\u003e41899M, 27-41899M\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003eCV25ELD, CV25EMLD, CV30ELD\u003c\/td\u003e\n        \u003ctd\u003e25–30\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1990\u003c\/td\u003e\n        \u003ctd\u003e41899M, 27-41899M\u003c\/td\u003e\n        \u003ctd\u003e\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/Mariner\u003c\/td\u003e\n        \u003ctd\u003eC25ELHP, C25ELRP, C30ELRP, C30ERP\u003c\/td\u003e\n        \u003ctd\u003e25–30\u003c\/td\u003e\n        \u003ctd\u003e2-Stroke\u003c\/td\u003e\n        \u003ctd\u003e1991\u003c\/td\u003e\n        \u003ctd\u003e41899M, 27-41899M\u003c\/td\u003e\n        \u003ctd\u003e\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\u003eLower Unit Gasket Seal Kit\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eLower Unit\/Gear Case\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n    \u003cli\u003ePlace a drain pan under the lower unit and remove the upper (vent) and lower drain screws to empty the gear oil.\u003c\/li\u003e\n    \u003cli\u003eRemove the bolts securing the lower unit to the engine's midsection.\u003c\/li\u003e\n    \u003cli\u003eCarefully lower and detach the gearcase assembly. You may need to disconnect the shift shaft linkage first.\u003c\/li\u003e\n    \u003cli\u003eDisassemble the lower unit as required to access the old seals and gaskets (e.g., water pump housing, bearing carriers).\u003c\/li\u003e\n    \u003cli\u003eThoroughly clean all mating surfaces, removing any old gasket material or sealant residue. A plastic scraper can prevent gouging aluminum surfaces.\u003c\/li\u003e\n    \u003cli\u003eInstall the new gaskets, seals, and O-rings from the kit. Lightly oil new seals to ease installation and prevent damage.\u003c\/li\u003e\n    \u003cli\u003eReassemble the lower unit components, torquing all fasteners to the manufacturer's specifications found in your service manual.\u003c\/li\u003e\n    \u003cli\u003eReattach the lower unit to the engine, ensuring the driveshaft, water tube, and shift shaft are correctly aligned.\u003c\/li\u003e\n    \u003cli\u003eUsing a gear lube pump, refill the gearcase through the bottom drain hole until lube flows from the upper vent hole.\u003c\/li\u003e\n    \u003cli\u003eInstall the upper vent screw, then quickly remove the pump and install the lower drain screw. Always use new washers on the drain screws.\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 lower unit gaskets are failing?\u003c\/summary\u003e\n  \u003cp\u003eThe most common sign is \"milky\" or cloudy gear oil, which indicates water has mixed with the lubricant. Other symptoms include visible oil leaks from the propeller shaft, driveshaft, or shift shaft seals, or a persistent drop in the gear lube level.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eDoes this kit fit all 25-30HP Mercury engines?\u003c\/summary\u003e\n  \u003cp\u003eNo. This kit is specifically for the 2-stroke, 2-cylinder models manufactured between 1984–1991. It is critical to check your engine's model, serial number, and year against our compatibility chart to ensure a correct fit.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat are the signs of a failed lower unit seal?\u003c\/summary\u003e\n  \u003cp\u003eTelltale signs include finding water-contaminated (milky) gear lube, observing oil drips from the seals around the propeller or driveshaft, or noticing the gear oil level is consistently low. Any of these symptoms warrant an inspection and likely a reseal.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eAre any special tools required for installation?\u003c\/summary\u003e\n  \u003cp\u003eWhile many steps can be completed with standard mechanic's tools, a proper and safe installation often requires specialized equipment such as a seal puller, a bearing carrier puller, and a torque wrench. We strongly recommend consulting your engine's factory service manual for detailed procedures.\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\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\/section\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":50723800383803,"sku":"24MSK722R","price":40.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/24MSK722R.png?v=1763032143","url":"https:\/\/seasierra.com\/products\/lower-unit-gasket-seal-kit-fits-mercury-mariner-25-30hp-replaces-27-8m0089639-95220a1","provider":"SeaSierra","version":"1.0","type":"link"}