{"product_id":"water-shutter-assembly-fits-mercruiser-v6-v8-engines-replaces-807166a1-807166a2","title":"Water Shutter Assembly – Fits MerCruiser V6\/V8 Engines (Replaces 807166A1, 807166A2)","description":"\u003ch2\u003eWater Shutter Assembly – Fits MerCruiser V6\/V8 Engines (Replaces 807166A1, 807166A2)\u003c\/h2\u003e\n\u003cp\u003eThis water shutter assembly is designed for MerCruiser V6 and V8 sterndrive engines from 1996 to the present, including 4.3L (262 CID), 5.0L (305 CID), and 5.7L (350 CID) models equipped with a two-piece exhaust manifold.\u003c\/p\u003e\n\u003cp\u003eThis component is a direct replacement for MerCruiser part numbers 807166A1, 807166A2, and the 807166A3 kit. It serves the critical function of preventing water from flowing back into the engine through the exhaust system, which can cause severe damage like engine hydrolock.\u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eInstallation Location:\u003c\/strong\u003e Mounts inside the exhaust Y-Pipe.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eEngine Compatibility:\u003c\/strong\u003e Fits gasoline MerCruiser V6 \u0026amp; V8 engines (1996+).\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eComplete Kit:\u003c\/strong\u003e Includes the water shutter and two required grommets for a drop-in installation.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Cross-Reference\u003c\/h2\u003e\n\u003cp\u003eUse this table to confirm equivalent part numbers across OEM and aftermarket brands.\u003c\/p\u003e\n\u003cdiv style=\"overflow-x:auto;\"\u003e\n\u003ctable\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\u003e807166A1\u003c\/td\u003e\n            \u003ctd\u003eShutter\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eMerCruiser\u003c\/td\u003e\n            \u003ctd\u003e807166A2\u003c\/td\u003e\n            \u003ctd\u003eShutter\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eMerCruiser\u003c\/td\u003e\n            \u003ctd\u003e807166A3\u003c\/td\u003e\n            \u003ctd\u003eKit (includes shutter and grommets)\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\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\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\u003eRated HP\u003c\/th\u003e\n            \u003cth\u003eStroke\u003c\/th\u003e\n            \u003cth\u003eYears\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 V6\u003c\/td\u003e\n            \u003ctd\u003eVarious\u003c\/td\u003e\n            \u003ctd\u003e4-Stroke\u003c\/td\u003e\n            \u003ctd\u003e1996+\u003c\/td\u003e\n            \u003ctd\u003e807166A1\/A2\u003c\/td\u003e\n            \u003ctd\u003eWith Gen+ engines and 2-piece manifold\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eMerCruiser\u003c\/td\u003e\n            \u003ctd\u003eV6 \u0026amp; V8\u003c\/td\u003e\n            \u003ctd\u003eVarious\u003c\/td\u003e\n            \u003ctd\u003e4-Stroke\u003c\/td\u003e\n            \u003ctd\u003e1996+\u003c\/td\u003e\n            \u003ctd\u003e807166A1\u003c\/td\u003e\n            \u003ctd\u003eGen+ with larger Y-pipe\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003eMerCruiser\u003c\/td\u003e\n            \u003ctd\u003eAlpha\/Bravo\u003c\/td\u003e\n            \u003ctd\u003eVarious\u003c\/td\u003e\n            \u003ctd\u003e4-Stroke\u003c\/td\u003e\n            \u003ctd\u003e1996+\u003c\/td\u003e\n            \u003ctd\u003e807166A1\u003c\/td\u003e\n            \u003ctd\u003eMust match Y-pipe model\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\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\u003e\u003cstrong\u003eProduct Type\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd\u003eExhaust Water Shutter Assembly\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003e\u003cstrong\u003eInstallation\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd\u003eY-Pipe\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003e\u003cstrong\u003eFuel Type\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd\u003eGasoline\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003e\u003cstrong\u003eConnection\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd\u003eDrop-in with grommets\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003e\u003cstrong\u003eHousing Material\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd\u003eRubber with steel rod\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003e\u003cstrong\u003eHousing Color\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd\u003eBlack\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003e\u003cstrong\u003eFitting Type\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd\u003eDrop-in\u003c\/td\u003e\n        \u003c\/tr\u003e\n        \u003ctr\u003e\n            \u003ctd\u003e\u003cstrong\u003eOther Technical Attributes\u003c\/strong\u003e\u003c\/td\u003e\n            \u003ctd\u003ePrevents water backflow into engine; failure can result in engine hydrolock\u003c\/td\u003e\n        \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003ePackage Contents\u003c\/h2\u003e\n\u003cul\u003e\n    \u003cli\u003e1 x Water Shutter Assembly (Replaces 807166A1\/807166A2)\u003c\/li\u003e\n    \u003cli\u003e\u003cspan style=\"color:red;\"\u003e2 x Grommets (Replaces 25-8M0204688)\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Guide\u003c\/h2\u003e\n\u003col\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSafety First:\u003c\/strong\u003e Disconnect the boat's battery before beginning work on the engine or exhaust systems.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAccess the Y-Pipe:\u003c\/strong\u003e Locate and access the exhaust Y-pipe where the upper exhaust hoses connect. This may require removing other components.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eRemove Old Shutter:\u003c\/strong\u003e Carefully remove the old, failed water shutter and its grommets from within the Y-pipe.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eClean the Surface:\u003c\/strong\u003e Thoroughly clean the mounting surfaces inside the Y-pipe to ensure a proper seal for the new grommets.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eInstall New Grommets:\u003c\/strong\u003e Insert the two new grommets into the designated holes inside the Y-pipe.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eInstall New Shutter:\u003c\/strong\u003e Carefully insert the pins of the new water shutter assembly into the grommets until it is securely seated.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eVerify Function:\u003c\/strong\u003e Ensure the shutter can swing open and closed freely without binding.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eReassemble Exhaust:\u003c\/strong\u003e Reconnect any exhaust hoses or components that were removed for access.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFinal Check:\u003c\/strong\u003e Reconnect the battery. Start the engine and check for any exhaust or water leaks around the service area.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eHow do I know if I need to replace my water shutter?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eCommon signs of a failed water shutter include a rattling noise from the exhaust, evidence of water in the engine oil, engine overheating, or difficulty starting. The most critical sign is finding water in the cylinders, which indicates \u003cstrong\u003eengine hydrolock\u003c\/strong\u003e, a severe condition that a functioning shutter helps prevent.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is the purpose of a water shutter?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt acts as a one-way valve located in your exhaust Y-pipe. It opens to let exhaust gases out when the engine is running and closes to prevent water from flowing back into the engine cylinders when the engine is off or when decelerating quickly.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat engines does this water shutter assembly fit?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIt is designed for a wide range of \u003cstrong\u003eMerCruiser V6 and V8 engines made from 1996 and onward\u003c\/strong\u003e, specifically those with \"Gen+\" (Generation Plus) architecture and a two-piece exhaust manifold. Always confirm your engine model and year before ordering.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs this a single part or a complete kit?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThis is a complete replacement assembly that includes one \u003cstrong\u003ewater shutter and a pair of new grommets\u003c\/strong\u003e required for a proper installation. This corresponds to what MerCruiser sells as kit 807166A3.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eOEM vs. Aftermarket?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThis 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\u003cp\u003e\u003cstrong\u003eHow fast do you ship and how much does it cost?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eWe 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\u003cp\u003e\u003cstrong\u003eWhat is your warranty and return policy?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThis 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\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\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\n","brand":"JLM Marine","offers":[{"title":"Default Title","offer_id":51313354932537,"sku":"QM-807166A2","price":25.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0885\/0433\/6697\/files\/QM-807166A2_7b622f12-f7d5-4398-93df-8f47d20b002d.png?v=1762188397","url":"https:\/\/jlmmarine.com\/products\/water-shutter-assembly-fits-mercruiser-v6-v8-engines-replaces-807166a1-807166a2","provider":"JLM Marine Boat Parts Limited","version":"1.0","type":"link"}