{"product_id":"serpentine-belt-idler-pulley-fits-mercruiser-4-3-5-0-5-7-6-2l-v6-v8-engines-replaces-864625t-807757t","title":"Serpentine Belt Idler Pulley – Fits MerCruiser 4.3, 5.0, 5.7, 6.2L V6\/V8 Engines (Replaces 864625T, 807757T)","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 aftermarket \u003cstrong\u003eSerpentine Belt Idler Pulley\u003c\/strong\u003e is designed for a precise fit on a range of Mercury MerCruiser engines, including 4.3L (V6), 5.0L (V8), 5.7L (V8), and 6.2L (V8) models with stern drive or inboard configurations. It ensures proper belt tension and guidance for reliable engine accessory operation.\u003c\/p\u003e\n\u003cp\u003eThis component is a direct interchange for Mercury\/MerCruiser part numbers 864625T and 807757T, as well as Sierra part number 18-6457.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eEngineered as a direct replacement for a straightforward installation.\u003c\/li\u003e\n\u003cli\u003eBuilt to withstand demanding marine environments.\u003c\/li\u003e\n\u003cli\u003eIncludes one high-quality idler pulley.\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\/MerCruiser\u003c\/td\u003e\n        \u003ctd\u003e864625T\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury\/MerCruiser\u003c\/td\u003e\n        \u003ctd\u003e807757T\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra\u003c\/td\u003e\n        \u003ctd\u003e18-6457\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\u003eThis pulley is compatible with the following MerCruiser engines:\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\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\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003e4.3L\u003c\/td\u003e\n        \u003ctd\u003e190-220\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e864625T\u003c\/td\u003e\n        \u003ctd\u003eV6 Engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003e5.0L\u003c\/td\u003e\n        \u003ctd\u003e220-260\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e864625T\u003c\/td\u003e\n        \u003ctd\u003eV8 Engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003e5.7L\u003c\/td\u003e\n        \u003ctd\u003e260-300\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e864625T\u003c\/td\u003e\n        \u003ctd\u003eV8 Engine\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003e6.2L\u003c\/td\u003e\n        \u003ctd\u003e320\u003c\/td\u003e\n        \u003ctd\u003e4-Stroke\u003c\/td\u003e\n        \u003ctd\u003e864625T\u003c\/td\u003e\n        \u003ctd\u003eV8 Engine\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\u003eSerpentine Belt Idler Pulley\u003c\/dd\u003e\n  \u003cdt\u003eInstallation\u003c\/dt\u003e\n\u003cdd\u003eDirect replacement\u003c\/dd\u003e\n  \u003cdt\u003eDimensions\u003c\/dt\u003e\n\u003cdd\u003e4.25\" diameter (108 mm)\u003c\/dd\u003e\n  \u003cdt\u003eWeight\u003c\/dt\u003e\n\u003cdd\u003e0.38 lbs (0.17 kg)\u003c\/dd\u003e\n  \u003cdt\u003eFitting Type\u003c\/dt\u003e\n\u003cdd\u003eDirect mount\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat’s in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cspan style=\"color:#d0021b;\"\u003e1 x\u003c\/span\u003e Idler Pulley (864625T)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect the boat's battery for safety.\u003c\/li\u003e\n  \u003cli\u003eLocate the serpentine belt tensioner to relieve tension from the belt.\u003c\/li\u003e\n  \u003cli\u003eCarefully remove the serpentine belt from the old idler pulley.\u003c\/li\u003e\n  \u003cli\u003eUnbolt and remove the old idler pulley from its mounting point.\u003c\/li\u003e\n  \u003cli\u003eInstall the new idler pulley, ensuring it is properly seated.\u003c\/li\u003e\n  \u003cli\u003eTighten the mounting bolt to the manufacturer's recommended torque specification.\u003c\/li\u003e\n  \u003cli\u003eRoute the serpentine belt according to your engine's diagram.\u003c\/li\u003e\n  \u003cli\u003eRe-apply tension to the belt using the tensioner.\u003c\/li\u003e\n  \u003cli\u003eReconnect the battery and start the engine to verify smooth operation and proper belt tracking.\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 idler pulley is failing?\u003c\/summary\u003e\n  \u003cp\u003eCommon signs of a worn idler pulley include a persistent squealing, chirping, or grinding noise from the engine bay, visible wobble or play in the pulley, or physical damage like cracks or chips on the pulley surface.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat is the function of the idler pulley?\u003c\/summary\u003e\n  \u003cp\u003eAn idler pulley guides the serpentine belt and helps maintain correct tension as it moves. This ensures accessories like the alternator, water pump, and power steering pump are driven effectively and without slippage.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eIs a special tool required for installation?\u003c\/summary\u003e\n  \u003cp\u003eA standard socket or wrench set is required to remove the mounting bolt. A belt tensioner tool or a long-handled breaker bar may also be needed to release the tension on the serpentine belt, depending on your engine's specific tensioner design.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eDoes this pulley come with a new bolt?\u003c\/summary\u003e\n  \u003cp\u003eThis package contains the idler pulley only. The original factory mounting bolt is typically reused. Inspect the bolt for corrosion or damage before reinstalling.\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\u003ePro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n  \u003cli\u003eFast Global Fulfillment — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n  \u003cli\u003eManufacturer-Direct Value — 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":50723789898043,"sku":"23TP206OC","price":22.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/23TP206OC.png?v=1763031836","url":"https:\/\/seasierra.com\/products\/serpentine-belt-idler-pulley-fits-mercruiser-4-3-5-0-5-7-6-2l-v6-v8-engines-replaces-864625t-807757t","provider":"SeaSierra","version":"1.0","type":"link"}