{"product_id":"lower-unit-oil-seal-fits-yamaha-50-100-hp-outboards-replaces-93101-25m03-00","title":"Lower Unit Oil Seal – Fits Yamaha 50-100 HP Outboards (Replaces 93101-25M03-00)","description":"\n\u003ch2\u003eLower Unit Oil Seal – Fits Yamaha 50-100 HP Outboards (Replaces 93101-25M03-00)\u003c\/h2\u003e\n\u003cp\u003eThis lower unit oil seal is engineered for Yamaha 50-100 HP 2-Stroke \u0026amp; 4-Stroke outboards that utilize a 25×40×6 mm S-type seal. It serves as a direct-fit replacement, ensuring a reliable barrier against water intrusion and oil leaks in the gearcase.\u003c\/p\u003e\n\u003cp\u003eThis component is a direct replacement for Yamaha part number \u003cstrong\u003e93101-25M03-00\u003c\/strong\u003e and Sierra \u003cstrong\u003e18-0587\u003c\/strong\u003e. It is also the same seal included in aftermarket kits from REPLACEMENTKITS.COM and SupremeMarine.\u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 25 mm (inner) × 40 mm (outer) × 6 mm (width)\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e High-grade rubber with a metal spring reinforcement for a secure, long-lasting seal.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Designed for use as a driveshaft and\/or propshaft seal in the lower unit.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Cross-Reference\u003c\/h2\u003e\n\u003cp\u003eUse this table to confirm equivalent part numbers across OEM and aftermarket brands.\u003c\/p\u003e\n\u003ctable\u003e\n    \u003cthead\u003e\n        \u003ctr\u003e\n            \u003cth\u003eBrand\u003c\/th\u003e\n            \u003cth\u003ePart Number\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\u003eYamaha\u003c\/td\u003e\n            \u003ctd\u003e93101-25M03-00\u003c\/td\u003e\n            \u003ctd\u003eOEM Part\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eSierra\u003c\/td\u003e\n            \u003ctd\u003e18-0587\u003c\/td\u003e\n            \u003ctd\u003eAftermarket Equivalent\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eREPLACEMENTKITS.COM\u003c\/td\u003e\n            \u003ctd\u003eKit\u003c\/td\u003e\n            \u003ctd\u003eThis seal is included in their kit.\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eSupremeMarine\u003c\/td\u003e\n            \u003ctd\u003e9310125M03 Kit\u003c\/td\u003e\n            \u003ctd\u003eThis seal is included in their kit.\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\u003cp\u003eConfirm your engine model\/year in the table below. For Yamaha owners, here’s a guide to help you identify your engine’s serial\/model: \u003ca href=\"https:\/\/jlmmarine.com\/blogs\/serial-number-guide\/yamaha-outboard-serial-number-guide-2025\" rel=\"nofollow noopener\" target=\"_blank\"\u003eYamaha Serial Number Guide\u003c\/a\u003e. You can also review exploded diagrams to verify part numbers: \u003ca href=\"https:\/\/jlmmarine.com\/blogs\/serial-number-guide\/yamaha-outboard-parts-diagrams-catalog\" rel=\"nofollow noopener\" target=\"_blank\"\u003eYamaha Parts Diagrams \u0026amp; Catalog\u003c\/a\u003e.\u003c\/p\u003e\n\u003ctable\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\u003eYamaha\u003c\/td\u003e\n            \u003ctd\u003eVarious\u003c\/td\u003e\n            \u003ctd\u003e50-100\u003c\/td\u003e\n            \u003ctd\u003e2-Stroke \u0026amp; 4-Stroke\u003c\/td\u003e\n            \u003ctd\u003e93101-25M03-00\u003c\/td\u003e\n            \u003ctd\u003eLower unit seal\u003c\/td\u003e\n        \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable\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\u003eProduct Type\u003c\/td\u003e\n            \u003ctd\u003eLower Unit Oil Seal (S-Type)\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eInstallation Location\u003c\/td\u003e\n            \u003ctd\u003eLower Unit\/Gearcase\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eDimensions\u003c\/td\u003e\n            \u003ctd\u003e\n\u003cstrong\u003e25 mm × 40 mm × 6 mm\u003c\/strong\u003e (inner × outer × width)\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eMaterial\u003c\/td\u003e\n            \u003ctd\u003eRubber with metal spring reinforcement\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eSeal Type\u003c\/td\u003e\n            \u003ctd\u003eS-Type\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eColor\u003c\/td\u003e\n            \u003ctd\u003eBlack\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eReplaces OEM Part Number\u003c\/td\u003e\n            \u003ctd\u003e93101-25M03-00\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eApplication\u003c\/td\u003e\n            \u003ctd\u003eDriveshaft\/Propshaft Seal\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eQuantity Per Engine\u003c\/td\u003e\n            \u003ctd\u003e2 seals typically required per lower unit\u003c\/td\u003e\n        \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003ePackage Contents\u003c\/h2\u003e\n\u003cp\u003ePackage contents depend on the purchase option:\u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eIndividual Part:\u003c\/strong\u003e 1 x S-Type Oil Seal (Replaces 93101-25M03-00)\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAftermarket Kits:\u003c\/strong\u003e \u003cspan style=\"color:red;\"\u003eContents vary. Most kits typically include two seals per package. Please verify the contents of the specific kit you are purchasing.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Guide\u003c\/h2\u003e\n\u003col\u003e\n    \u003cli\u003e\n\u003cstrong\u003eDrain Oil:\u003c\/strong\u003e Start by completely draining the gearcase oil into a suitable container.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eRemove Propeller \u0026amp; Lower Unit:\u003c\/strong\u003e Remove the propeller assembly. Then, unbolt and carefully detach the entire lower unit from the outboard's midsection.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAccess Seals:\u003c\/strong\u003e Secure the lower unit on a workbench to easily access the driveshaft and propeller shaft housings.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eExtract Old Seals:\u003c\/strong\u003e Carefully pry out the old oil seals using a seal puller or flat-head screwdriver. Take note of their orientation.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eClean Housing:\u003c\/strong\u003e Thoroughly clean the seal seating area inside the housing. Remove any old sealant, dirt, or corrosion.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eLubricate New Seals:\u003c\/strong\u003e Apply a light coat of marine grease to the inner and outer surfaces of the new oil seals.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eInstall Seals:\u003c\/strong\u003e Press the new seals into the housing using a seal driver or a socket of the appropriate diameter. Ensure they are seated evenly and facing the correct direction (typically, the spring side faces the oil).\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eReassemble:\u003c\/strong\u003e Re-install the lower unit, torquing the bolts to the manufacturer's specifications.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eRefill Gear Lube:\u003c\/strong\u003e Fill the gearcase with the recommended marine gear lubricant.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eCheck for Leaks:\u003c\/strong\u003e Before operating the outboard, check for any signs of oil leaks around the newly installed seals.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eHow do I know if this oil seal will fit my Yamaha outboard?\u003c\/strong\u003e\u003cbr\u003e\nThis seal is designed for most Yamaha 50-100 HP 2-Stroke and 4-Stroke outboards. The most reliable way to confirm fitment is by matching the OEM part number \u003cstrong\u003e93101-25M03-00\u003c\/strong\u003e or the dimensions \u003cstrong\u003e25mm x 40mm x 6mm\u003c\/strong\u003e to your existing seal.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat are the signs of a failing lower unit oil seal?\u003c\/strong\u003e\u003cbr\u003e\nCommon signs include a milky or cloudy appearance in your gear lube (indicating water intrusion), visible oil leaking from the propeller shaft area, or fishing line tangled around the propshaft, which can damage the seal.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow many seals do I need for a complete lower unit service?\u003c\/strong\u003e\u003cbr\u003e\nA typical lower unit service requires \u003cstrong\u003etwo\u003c\/strong\u003e of these seals—one for the driveshaft and one for the propeller shaft. We recommend replacing both simultaneously, but you should always verify your specific engine's requirements.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eOEM vs. Aftermarket?\u003c\/strong\u003e\u003cbr\u003e\nThis listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow fast do you ship and how much does it cost?\u003c\/strong\u003e\u003cbr\u003e\nWe offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is your warranty and return policy?\u003c\/strong\u003e\u003cbr\u003e\nThis product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused \u0026amp; in original condition); please see our policy page or reach out for instructions.\u003c\/p\u003e\n\n\u003ch2\u003eImportant Notes\u003c\/h2\u003e\n\u003cul\u003e\n    \u003cli\u003eVerify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.\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\n\n\u003ch2\u003eWhy Choose JLM MARINE?\u003c\/h2\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eQuality Assured:\u003c\/strong\u003e As a trusted manufacturer for over 20 years, we supply top marine brands globally.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFast Global Shipping:\u003c\/strong\u003e Free delivery worldwide in 5–15 days.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eDirect from Manufacturer:\u003c\/strong\u003e Competitive pricing without compromising quality.\u003c\/li\u003e\n\u003c\/ul\u003e\n","brand":"JLM Marine","offers":[{"title":"Default Title","offer_id":51313357095225,"sku":"KF2807 x 2","price":23.99,"currency_code":"USD","in_stock":true}],"url":"https:\/\/jlmmarine.com\/es\/products\/lower-unit-oil-seal-fits-yamaha-50-100-hp-outboards-replaces-93101-25m03-00","provider":"JLM Marine Boat Parts Limited","version":"1.0","type":"link"}