{"product_id":"11-859135-lower-gear-casing-mounting-nut-for-mercruiser-alpha-one-gen-ii-jlm-marine","title":"11-859135 Lower Gear Casing Mounting Nut for MerCruiser Alpha One Gen II | JLM Marine","description":"\u003ch2\u003eLower Gear Casing Mounting Nut – Fits MerCruiser Alpha One Gen II\u003c\/h2\u003e\n\n\u003cp\u003eThis \u003cstrong\u003elower gear casing mounting nut\u003c\/strong\u003e is engineered to fit \u003cstrong\u003eMerCruiser Alpha One Gen II\u003c\/strong\u003e stern drives. Designed as a direct replacement for part number \u003cstrong\u003e11-859135\u003c\/strong\u003e, it ensures secure mounting and reliable performance in demanding marine environments.\u003c\/p\u003e\n\n\u003cp\u003eThis aftermarket component directly replaces OEM part numbers \u003cstrong\u003e11-817618\u003c\/strong\u003e and \u003cstrong\u003e11-859135\u003c\/strong\u003e (also listed as 859135), providing a cost-effective solution without compromising quality or fitment.\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003ePrecision-engineered for Alpha One Gen II applications\u003c\/li\u003e\n\u003cli\u003eDirect fit for lower gear casing assembly (see diagram part 76)\u003c\/li\u003e\n\u003cli\u003eDurable construction for long-term marine use\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\u003cdiv style=\"overflow-x:auto;\"\u003e\n\u003ctable border=\"1\" cellpadding=\"8\" cellspacing=\"0\" style=\"border-collapse:collapse; width:100%;\"\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\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003e11-859135\u003c\/td\u003e\n\u003ctd\u003ePrimary OEM reference\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003e859135\u003c\/td\u003e\n\u003ctd\u003eAlternate listing\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003e11-817618\u003c\/td\u003e\n\u003ctd\u003eSuperseded by 11-859135\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\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\" style=\"border-collapse:collapse; width:100%;\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eModel\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\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003eAlpha One Gen II\u003c\/td\u003e\n\u003ctd\u003eLower gear casing mounting nut (Part 76 in exploded diagram)\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\" style=\"border-collapse:collapse; width:100%;\"\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\u003e11-859135\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eLower gear casing mounting\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFitment\u003c\/td\u003e\n\u003ctd\u003eMerCruiser Alpha One Gen II stern drives\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDiagram Reference\u003c\/td\u003e\n\u003ctd\u003ePart 76\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\u003cul\u003e\n\u003cli\u003e\n\u003cspan style=\"color:red;\"\u003e\u003cstrong\u003e1 × Lower Gear Casing Mounting Nut\u003c\/strong\u003e\u003c\/span\u003e (OEM# 11-859135)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Guide\u003c\/h2\u003e\n\n\u003col\u003e\n\u003cli\u003eEnsure the stern drive is properly supported and the lower unit is removed according to manufacturer service manual procedures.\u003c\/li\u003e\n\u003cli\u003eClean the mounting threads on the gear casing and inspect for damage or corrosion.\u003c\/li\u003e\n\u003cli\u003ePosition the lower gear casing alignment components as specified in your service manual.\u003c\/li\u003e\n\u003cli\u003eThread the mounting nut onto the gear casing by hand to prevent cross-threading.\u003c\/li\u003e\n\u003cli\u003eTorque the nut to the manufacturer's specification using a calibrated torque wrench (refer to your Alpha One Gen II service manual for exact values).\u003c\/li\u003e\n\u003cli\u003eVerify all alignment and clearances before reassembling the drive unit.\u003c\/li\u003e\n\u003cli\u003eReinstall the lower unit following MerCruiser service procedures and perform a functional test.\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 nut fits my MerCruiser drive?\u003c\/strong\u003e\u003cbr\u003e\nA: Verify your stern drive is an \u003cstrong\u003eAlpha One Gen II\u003c\/strong\u003e model. Cross-reference part number \u003cstrong\u003e11-859135\u003c\/strong\u003e or \u003cstrong\u003e11-817618\u003c\/strong\u003e in your service manual or exploded parts diagram (Part 76). If your original nut matches these specifications, this replacement will fit.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What torque specification should I use when installing this nut?\u003c\/strong\u003e\u003cbr\u003e\nA: Always follow the torque values specified in your MerCruiser Alpha One Gen II service manual. Over-tightening can damage threads or the gear casing; under-tightening may cause improper alignment or loosening during operation.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: When should I replace the lower gear casing mounting nut?\u003c\/strong\u003e\u003cbr\u003e\nA: Replace this nut if you notice thread damage, corrosion, deformation, or if it cannot achieve proper torque specification. It should also be inspected during any lower unit service or gear casing work.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What's the difference between this aftermarket nut and the OEM part?\u003c\/strong\u003e\u003cbr\u003e\nA: This aftermarket replacement is manufactured to OEM specifications using comparable-grade materials. It provides the same fitment and function as the original MerCruiser part at a more competitive price point.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Is this part OEM or aftermarket?\u003c\/strong\u003e\u003cbr\u003e\nA: This 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\n\u003cp\u003e\u003cstrong\u003eQ: How fast do you ship and how much does it cost?\u003c\/strong\u003e\u003cbr\u003e\nA: We 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\n\u003cp\u003e\u003cstrong\u003eQ: What is your warranty and return policy?\u003c\/strong\u003e\u003cbr\u003e\nA: This 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\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\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","brand":"JLM Marine","offers":[{"title":"Default Title","offer_id":51981004570937,"sku":"23PN479","price":7.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0885\/0433\/6697\/files\/10_e29bd136-cc49-4205-9971-7c64fcace65f.jpg?v=1772455181","url":"https:\/\/jlmmarine.com\/products\/11-859135-lower-gear-casing-mounting-nut-for-mercruiser-alpha-one-gen-ii-jlm-marine","provider":"JLM Marine Boat Parts Limited","version":"1.0","type":"link"}