{"product_id":"merc-266","title":"Mercury MerCruiser 42799 Water Pump Pulley — 2-Groove, GM V8 Sterndrive \u0026 Inboard","description":"\u003csection class=\"product-description\"\u003e\n\n\u003ch2\u003eMercury MerCruiser 42799 — 2-Groove Water Pump Pulley, GM V8 Sterndrive \u0026amp; Inboard\u003c\/h2\u003e\n\n\u003ctable\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003cth\u003ePart Number\u003c\/th\u003e\n\u003ctd\u003e42799\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eSKU\u003c\/th\u003e\n\u003ctd\u003e42799\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eMercury \/ MerCruiser (OEM)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eProduct Type\u003c\/th\u003e\n\u003ctd\u003eWater Pump Pulley — 2-Groove\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eSystem\u003c\/th\u003e\n\u003ctd\u003eMerCruiser GM V8 Front Accessory Drive \/ Cooling System\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eGroove Count\u003c\/th\u003e\n\u003ctd\u003e2-groove\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eRelated Hardware\u003c\/th\u003e\n\u003ctd\u003ePulley-to-water-pump screw: 47277 \/ Lock washer: 39107\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eDimensions (pkg)\u003c\/th\u003e\n\u003ctd\u003eapprox. 7.63\" L × 6.25\" W × 5.00\" H\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eWeight\u003c\/th\u003e\n\u003ctd\u003eapprox. 960 g (2.11 lb)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eAvailability\u003c\/th\u003e\n\u003ctd\u003eDiscontinued \/ No Longer Available from Mercury — remaining stock only\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eHTS Code\u003c\/th\u003e\n\u003ctd\u003e848350\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eOverview\u003c\/h2\u003e\n\u003cp\u003eThe Mercury MerCruiser 42799 is a 2-groove water pump pulley for select older MerCruiser GM-based V8 sterndrive and inboard engines. It mounts to the engine’s circulating water pump and drives the accessory belt arrangement on the matching front-cover and intake-manifold assembly. This part is \u003cstrong\u003ediscontinued and no longer available from Mercury\u003c\/strong\u003e — once existing stock is gone, no further supply is expected. If you need this pulley, order before stock clears.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFitment note:\u003c\/strong\u003e Pulley fitment depends on the exact engine model, serial number range, water pump style, crankshaft pulley arrangement, and whether the engine uses a 2-groove or 3-groove pulley setup. Always confirm using the MerCruiser engine serial number before ordering — older GM V8 engines used multiple front-drive pulley arrangements that are not interchangeable.\u003c\/p\u003e\n\n\u003ch2\u003eCompatible Applications\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eMerCruiser 230 MIE — 2-groove front accessory drive (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003eMerCruiser 260 MIE — 2-groove front accessory drive (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003eMerCruiser 5.0L \/ 305 CID — selected configurations (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003eMerCruiser 5.0L MIE — selected configurations (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003eMerCruiser 5.7L \/ 350 CID — selected configurations (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003eMerCruiser 5.7L MIE — selected configurations (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003eMerCruiser 5.7L Ski — selected configurations (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003eMerCruiser 5.7L Competition Ski — selected configurations (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003eMerCruiser 330 GM 454 — selected configurations (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003eMerCruiser 340 MIE — selected configurations (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003eMerCruiser 7.4L \/ 454 CID MIE — selected configurations (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003eMerCruiser 454 Mag Alpha — selected configurations (confirm serial range)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAlways confirm by engine model and serial number\u003c\/strong\u003e — multiple front-drive pulley layouts were used across these engine families and serial ranges\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWhen to Replace\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003ePulley is bent, cracked, or has visible physical damage\u003c\/li\u003e\n  \u003cli\u003ePulley is wobbling or misaligned at the water pump shaft\u003c\/li\u003e\n  \u003cli\u003eGroove wear is accelerating belt wear or causing belt tracking issues\u003c\/li\u003e\n  \u003cli\u003eSquealing, vibration, or repeated belt failure is traced to pulley condition\u003c\/li\u003e\n  \u003cli\u003eHeavy rust or corrosion is compromising structural integrity or belt contact surfaces\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eConfirm the replacement pulley matches the groove count (2-groove) and pulley diameter of the original — do not substitute a 3-groove pulley where a 2-groove is required\u003c\/li\u003e\n  \u003cli\u003eInspect the circulating water pump, pulley mounting surface, and belt alignment before installation\u003c\/li\u003e\n  \u003cli\u003eRelated hardware: pulley-to-water-pump screw \u003cstrong\u003e47277\u003c\/strong\u003e and lock washer \u003cstrong\u003e39107\u003c\/strong\u003e — replace if worn or corroded\u003c\/li\u003e\n  \u003cli\u003eAfter installation, verify belt tracking and alignment across all driven pulleys before running the engine\u003c\/li\u003e\n  \u003cli\u003eInspect the serpentine or V-belt for wear while the pulley is off — replace if cracking, glazing, or fraying is found\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTechnical FAQ\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eWhy does the groove count matter?\u003c\/strong\u003e The 2-groove pulley is matched to a specific belt and crankshaft pulley arrangement. Installing a 3-groove pulley where a 2-groove is required (or vice versa) results in belt misalignment, belt failure, or accessory drive damage. Always match by groove count and serial-confirmed application.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThis part is discontinued — what are my options if it’s unavailable?\u003c\/strong\u003e If OEM stock is exhausted, options include sourcing a compatible aftermarket equivalent or having a machined replacement fabricated. Confirm dimensions and groove profile before substituting any non-OEM part. A marine engine specialist familiar with older MerCruiser GM V8 setups is the best resource for alternative sourcing.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCan I reuse the pulley screws and lock washers?\u003c\/strong\u003e Inspect them closely. If they show corrosion, thread damage, or have been previously overtightened, replace with Mercury OEM hardware (screw 47277, lock washer 39107) or equivalent-spec fasteners. Fastener failure on a water pump pulley can cause immediate belt and cooling system damage.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMy belt keeps slipping after installing a new pulley — what should I check?\u003c\/strong\u003e Verify pulley alignment with all other driven pulleys using a straightedge. Misalignment from a worn water pump bearing is a common cause of belt slip or tracking issues on older GM V8 MerCruiser engines.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eParts Desk Insights\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eBest Use Case:\u003c\/strong\u003e This pulley is the right part when an older MerCruiser GM V8 engine is losing belts, showing vibration from a damaged or worn water pump pulley, or being rebuilt and the original pulley is beyond reuse. Because it’s discontinued, it’s worth ordering as a spare at the same time if the engine is a long-term keeper — once stock is gone, sourcing this pulley becomes difficult.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCommon Issues:\u003c\/strong\u003e The most frequent mistake is not confirming the groove count before ordering. A 3-groove pulley from a similar engine looks nearly identical but will cause immediate belt misalignment. The second common issue is assuming the pulley is the problem when the water pump bearing has actually failed — a failed bearing causes wobble that damages the pulley and belt, so always inspect the pump before ordering a replacement pulley.\u003c\/p\u003e\n\n\u003ch2\u003eRelated Products\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003ca href=\"https:\/\/marisolmarine.com\/products\/mercury-807730t-crankshaft-pulley-mercruiser-gm-v6-v8-serpentine\"\u003eMercury 807730T Crankshaft Pulley — MerCruiser GM V6 \u0026amp; V8 Serpentine\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"https:\/\/marisolmarine.com\/products\/mercury-mercruiser-seawater-pump-pulley-8m0150724\"\u003eMercury MerCruiser Seawater Pump Pulley — 8M0150724\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"https:\/\/marisolmarine.com\/products\/mercury-mercruiser-power-steering-pump-pulley-8m0150723\"\u003eMercury MerCruiser Power Steering Pump Pulley — 8M0150723\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"https:\/\/marisolmarine.com\/products\/mercury-mercruiser-idler-pulley-864625t\"\u003eMercury MerCruiser Idler Pulley 864625T — 6-Groove Serpentine, 4.25\" OD\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"https:\/\/marisolmarine.com\/products\/mercury-mercruiser-serpentine-belt-pulley-kit-8m0150824\"\u003eMercury MerCruiser Serpentine Belt \u0026amp; Pulley Kit — 8M0150824\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"https:\/\/marisolmarine.com\/products\/mercury-mercruiser-quicksilver-serpentine-belt-865615q04\"\u003eMercury MerCruiser Quicksilver Serpentine Belt 865615Q04\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"https:\/\/marisolmarine.com\/products\/mercury-quicksilver-865615q06-mercruiser-serpentine-belt\"\u003eMercury Quicksilver 865615Q06 Serpentine Belt — MerCruiser V8 5.0L–8.2L Sterndrive\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c\/section\u003e","brand":"MERC","offers":[{"title":"Default Title","offer_id":43563858755620,"sku":"42799","price":104.72,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/6de8cb61-5c02-43be-84e7-528882d5cf20.png?v=1777483567","url":"https:\/\/marisolmarine.com\/products\/merc-266","provider":"Marisol Marine Company","version":"1.0","type":"link"}