{"product_id":"865598-serpentine-belt-pulley-for-mercruiser","title":"865598 Serpentine Belt Pulley for MerCruiser | JLM Marine","description":"\u003ch2\u003eSerpentine Belt Pulley for MerCruiser – Fits 4.3L, 5.0L, 5.7L, 5.8L, 6.2L, 8.1L Engines\u003c\/h2\u003e\n\n\u003cp\u003eThis \u003cstrong\u003eSerpentine Belt Idler Pulley\u003c\/strong\u003e is designed for \u003cstrong\u003eMerCruiser\u003c\/strong\u003e inboard and stern drive engines, including \u003cstrong\u003e4.3L, 5.0L, 5.7L, 5.8L, 6.2L, and 8.1L\u003c\/strong\u003e models with Alpha and Bravo drives. Engineered to maintain proper belt tension and reduce vibration, this flat idler pulley ensures reliable performance in demanding marine environments.\u003c\/p\u003e\n\n\u003cp\u003eThis aftermarket pulley directly replaces OEM part numbers \u003cstrong\u003e8M6500024\u003c\/strong\u003e, \u003cstrong\u003e865598\u003c\/strong\u003e, \u003cstrong\u003e818382\u003c\/strong\u003e, and \u003cstrong\u003e710-8M6500024\u003c\/strong\u003e, providing a cost-effective solution without compromising quality or fitment.\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePulley Size:\u003c\/strong\u003e 3-3\/16\" flat idler design for serpentine belt systems\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Engine idler pulley for MerCruiser stern drive and inboard engines\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDirect Fit:\u003c\/strong\u003e Designed to OEM specifications for seamless installation\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\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\u003c\/td\u003e\n\u003ctd\u003e8M6500024\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003e865598\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003e818382\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAftermarket\u003c\/td\u003e\n\u003ctd\u003e710-8M6500024\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\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eModel\u003c\/th\u003e\n\u003cth\u003eEngine Size\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\u003eInboard \u0026amp; Stern Drive\u003c\/td\u003e\n\u003ctd\u003e4.3L\u003c\/td\u003e\n\u003ctd\u003eAlpha \u0026amp; Bravo drives\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003eInboard \u0026amp; Stern Drive\u003c\/td\u003e\n\u003ctd\u003e5.0L\u003c\/td\u003e\n\u003ctd\u003eAlpha \u0026amp; Bravo drives\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003eInboard \u0026amp; Stern Drive\u003c\/td\u003e\n\u003ctd\u003e5.7L\u003c\/td\u003e\n\u003ctd\u003eAlpha \u0026amp; Bravo drives\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003eInboard \u0026amp; Stern Drive\u003c\/td\u003e\n\u003ctd\u003e5.8L\u003c\/td\u003e\n\u003ctd\u003eAlpha \u0026amp; Bravo drives\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003eInboard \u0026amp; Stern Drive\u003c\/td\u003e\n\u003ctd\u003e6.2L\u003c\/td\u003e\n\u003ctd\u003eAlpha \u0026amp; Bravo drives\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003eInboard \u0026amp; Stern Drive\u003c\/td\u003e\n\u003ctd\u003e8.1L\u003c\/td\u003e\n\u003ctd\u003eAlpha \u0026amp; Bravo drives\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\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\u003e865598, 8M6500024, 818382, 710-8M6500024\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePulley Size\u003c\/td\u003e\n\u003ctd\u003e3-3\/16\"\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eType\u003c\/td\u003e\n\u003ctd\u003eEngine Idler Pulley (Flat)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eSerpentine Belt System\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEngine Type\u003c\/td\u003e\n\u003ctd\u003eMerCruiser 4.3L, 5.0L, 5.7L, 5.8L, 6.2L, 8.1L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible Drives\u003c\/td\u003e\n\u003ctd\u003eAlpha, Bravo\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\u003eYour package includes:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"color:red;\"\u003e\u003cstrong\u003e1 × Serpentine Belt Idler Pulley (3-3\/16\", Flat Design)\u003c\/strong\u003e\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\u003eDisconnect the battery\u003c\/strong\u003e to prevent accidental engine start during installation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLocate the serpentine belt routing diagram\u003c\/strong\u003e on your engine or in your service manual. Take a photo for reference before removal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRelease belt tension\u003c\/strong\u003e by loosening the tensioner or adjusting bolt, then carefully slide the serpentine belt off the pulleys.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemove the mounting bolt\u003c\/strong\u003e securing the old idler pulley to the engine bracket.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInspect the mounting bracket and bolt\u003c\/strong\u003e for wear, corrosion, or damage; replace if necessary.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstall the new idler pulley\u003c\/strong\u003e onto the mounting bracket, ensuring proper alignment.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHand-tighten the mounting bolt\u003c\/strong\u003e first, then torque to manufacturer specifications (refer to your service manual).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRoute the serpentine belt\u003c\/strong\u003e back onto all pulleys following the diagram or photo you referenced earlier.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCheck belt alignment and tension\u003c\/strong\u003e to ensure the belt sits centered on all pulleys without slack or excessive tightness.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReconnect the battery\u003c\/strong\u003e and start the engine briefly to verify smooth operation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eListen for unusual noises\u003c\/strong\u003e such as squealing or rattling, which may indicate misalignment or improper tension.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePerform a final inspection\u003c\/strong\u003e after the first few hours of operation to confirm the pulley and belt remain properly seated.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eHow do I confirm this pulley fits my MerCruiser engine?\u003c\/strong\u003e\u003cbr\u003e\nVerify your engine displacement (4.3L, 5.0L, 5.7L, 5.8L, 6.2L, or 8.1L) and check that your current pulley measures 3-3\/16\" and is a flat idler type. Cross-reference your existing OEM part number (865598, 8M6500024, 818382, or 710-8M6500024) with the compatibility table above.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat are the signs that my idler pulley needs replacement?\u003c\/strong\u003e\u003cbr\u003e\nCommon symptoms include squealing or chirping noises from the belt area, visible wear or wobble in the pulley, excessive belt wear or fraying, or rough bearing rotation when spun by hand with the belt removed.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eHow often should I replace the serpentine belt idler pulley?\u003c\/strong\u003e\u003cbr\u003e\nInspect the idler pulley during routine maintenance or whenever replacing the serpentine belt. Replace it if you notice roughness, play, or noise, or approximately every 3–5 years depending on operating hours and conditions.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCan I use this pulley if my engine has a different belt configuration?\u003c\/strong\u003e\u003cbr\u003e\nThis pulley is designed specifically for serpentine belt systems on the listed MerCruiser engines. If your engine uses a V-belt system or a different pulley diameter, this part will not be compatible.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eIs this an OEM pulley or an aftermarket replacement?\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\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\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\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":50990712226105,"sku":"23TP207","price":19.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0885\/0433\/6697\/files\/865598SerpentineFlatSmoothSurfaceIdler_a9f190cd-5256-4b8f-83dc-e0447a25b0e1.jpg?v=1755742188","url":"https:\/\/jlmmarine.com\/es\/products\/865598-serpentine-belt-pulley-for-mercruiser","provider":"JLM Marine Boat Parts Limited","version":"1.0","type":"link"}