{"product_id":"45518a2-shift-arm-for-mercruiser-mc-i-r-mr-alpha-one-gen-ii-jlm-marine","title":"45518A2 Shift Arm for Mercruiser MC-I R MR Alpha One Gen II | JLM Marine","description":"\u003ch2\u003e45518A2 Shift Arm for Mercruiser MC-I R MR Alpha One Gen II\u003c\/h2\u003e\n\n\u003cp\u003eThis aftermarket shift arm is designed to fit \u003cstrong\u003eMercruiser Stern Drive units\u003c\/strong\u003e, including \u003cstrong\u003eMC-I, R, MR, Alpha One, and Gen II\u003c\/strong\u003e models. It provides reliable shifting performance and is built to meet OEM specifications for durability and precise engagement.\u003c\/p\u003e\n\n\u003cp\u003eThis part directly replaces OEM part numbers \u003cstrong\u003e45518A1, 45518A2, and 45518A3\u003c\/strong\u003e, as well as aftermarket equivalents from Sierra (\u003cstrong\u003e18-2161\u003c\/strong\u003e), GLM (\u003cstrong\u003e21140\u003c\/strong\u003e), and Mallory (\u003cstrong\u003e9-72153\u003c\/strong\u003e), ensuring broad compatibility across multiple sourcing options.\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eCompatible with MC-I, R, MR, Alpha One \u0026amp; Gen II stern drives\u003c\/li\u003e\n  \u003cli\u003eReplaces multiple OEM and aftermarket part numbers\u003c\/li\u003e\n  \u003cli\u003eSold in a \u003cstrong\u003e5-piece kit\u003c\/strong\u003e for multiple replacements or backup stock\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\u003eMercruiser (OEM)\u003c\/td\u003e\n      \u003ctd\u003e45518A1\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMercruiser (OEM)\u003c\/td\u003e\n      \u003ctd\u003e45518A2\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMercruiser (OEM)\u003c\/td\u003e\n      \u003ctd\u003e45518A3\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eSierra\u003c\/td\u003e\n      \u003ctd\u003e18-2161\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eGLM\u003c\/td\u003e\n      \u003ctd\u003e21140\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMallory\u003c\/td\u003e\n      \u003ctd\u003e9-72153\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\" target=\"_blank\" rel=\"nofollow noopener\"\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\" target=\"_blank\" rel=\"nofollow noopener\"\u003eMercury Parts Diagrams \u0026amp; Catalog\u003c\/a\u003e.\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\u003eModel\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMercruiser Stern Drive\u003c\/td\u003e\n      \u003ctd\u003eMC-I\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMercruiser Stern Drive\u003c\/td\u003e\n      \u003ctd\u003eR\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMercruiser Stern Drive\u003c\/td\u003e\n      \u003ctd\u003eMR\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMercruiser Stern Drive\u003c\/td\u003e\n      \u003ctd\u003eAlpha One\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMercruiser Stern Drive\u003c\/td\u003e\n      \u003ctd\u003eGen II\u003c\/td\u003e\n    \u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\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 Number\u003c\/td\u003e\n      \u003ctd\u003e45518A2\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eApplication\u003c\/td\u003e\n      \u003ctd\u003eMercruiser Stern Drive MC-I, R, MR, Alpha One \u0026amp; Gen II\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eComponent Type\u003c\/td\u003e\n      \u003ctd\u003eShift Arm\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 kit includes \u003cspan style=\"color:red;\"\u003e\u003cstrong\u003e5 × Shift Arm\u003c\/strong\u003e\u003c\/span\u003e.\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Guide\u003c\/h2\u003e\n\n\u003col\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDisconnect power:\u003c\/strong\u003e Ensure the engine is off and the battery is disconnected to prevent accidental starting during the repair.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAccess the stern drive unit:\u003c\/strong\u003e Remove the lower unit following your service manual's instructions to expose the shift mechanism.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRemove the old shift arm:\u003c\/strong\u003e Carefully detach the existing shift arm by removing any retaining clips, pins, or fasteners that secure it in place.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInspect related components:\u003c\/strong\u003e Check the shift shaft, linkage, and cable for wear or damage; replace if necessary to ensure smooth operation.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eInstall the new shift arm:\u003c\/strong\u003e Position the replacement shift arm onto the shift shaft, aligning all mounting holes and connection points.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSecure with fasteners:\u003c\/strong\u003e Reinstall retaining clips, pins, or bolts to the manufacturer's torque specifications to prevent loosening.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReconnect shift linkage:\u003c\/strong\u003e Attach the shift cable or rod to the new shift arm, ensuring proper engagement and freedom of movement.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReassemble the lower unit:\u003c\/strong\u003e Reinstall the lower unit onto the stern drive, tightening all mounting bolts and checking alignment.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRefill gear oil:\u003c\/strong\u003e Add the correct grade and quantity of gear oil to the lower unit, checking for leaks at seals.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReconnect battery and test:\u003c\/strong\u003e Restore power, start the engine, and cycle through all shift positions (forward, neutral, reverse) to confirm smooth operation.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePerform a water test:\u003c\/strong\u003e Run the boat at idle and under load to verify that shifting is positive and free of slipping or binding.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRecheck fasteners:\u003c\/strong\u003e After initial use, inspect all bolts and connections to ensure nothing has loosened during operation.\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 shift arm fits my Mercruiser stern drive?\u003c\/strong\u003e\u003cbr\u003e\nA: Verify your stern drive model (MC-I, R, MR, Alpha One, or Gen II) and cross-reference your existing shift arm part number with the OEM numbers listed (45518A1, 45518A2, or 45518A3). Check the Compatible Engine Models table above or consult your service manual for confirmation.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What are the signs that my shift arm needs replacement?\u003c\/strong\u003e\u003cbr\u003e\nA: Common symptoms include difficulty shifting gears, grinding noises during gear changes, slipping out of gear under load, or the shift lever feeling loose or disconnected. Inspect the shift arm for cracks, excessive wear, or broken mounting points.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: How often should I replace the shift arm?\u003c\/strong\u003e\u003cbr\u003e\nA: Shift arms typically last many years under normal use. Replace only when you notice shifting problems, visible damage, or wear during routine lower unit maintenance. Always inspect the shift arm whenever servicing the lower unit or experiencing shift issues.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Can I use just one shift arm from this kit, or do I need to install all five?\u003c\/strong\u003e\u003cbr\u003e\nA: You need only one shift arm per stern drive unit. This kit includes five pieces for multiple replacements, backup inventory, or for marine service professionals who maintain multiple units.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What's the difference between this aftermarket shift arm and the OEM part?\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":51960670978361,"sku":"18SA001","price":63.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0885\/0433\/6697\/files\/57_b7193b83-b471-4de4-8dc2-29d4614d41e8.jpg?v=1771677646","url":"https:\/\/jlmmarine.com\/products\/45518a2-shift-arm-for-mercruiser-mc-i-r-mr-alpha-one-gen-ii-jlm-marine","provider":"JLM Marine Boat Parts Limited","version":"1.0","type":"link"}