{"product_id":"12644a1-18-4457-exhaust-4in-protector-flapper-for-mercruiser-mercury-sterndrive","title":"12644A1 18-4457 Exhaust 4in Protector Flapper for MerCruiser Mercury Sterndrive","description":"\u003cstrong\u003eThis Exhaust 4” Protector Flapper is a replacement exhaust shutter for MerCruiser and Mercury sterndrive systems and matches OEM Part# 12644A1, 18-4457.\u003c\/strong\u003e\u003ch2\u003eProduct Overview\u003c\/h2\u003e\u003cp\u003eThis exhaust protector flapper is a 4-inch diameter shutter that prevents water from entering the engine through the exhaust outlet when the boat is not running. It fits MerCruiser and Mercury sterndrive exhaust systems, providing essential protection against engine damage from backflow. The flapper assembly is a direct replacement for worn or missing exhaust shutters.\u003c\/p\u003e\u003ch3\u003eKey Features \u0026amp; Performance\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eDirect replacement for OEM part numbers 12644A1 and 18-4457\u003c\/li\u003e\n\u003cli\u003e4-inch diameter flapper fits standard MerCruiser and Mercury exhaust outlets\u003c\/li\u003e\n\u003cli\u003eStainless steel hinge pin for corrosion resistance\u003c\/li\u003e\n\u003cli\u003eRubber flapper closes automatically when engine is off to block water entry\u003c\/li\u003e\n\u003cli\u003eDurable construction withstands exhaust heat and marine environment\u003c\/li\u003e\n\u003cli\u003eEasy bolt-on installation without special tools\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment \u0026amp; Compatibility\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMerCruiser sterndrive models with 4-inch exhaust outlets\u003c\/li\u003e\n\u003cli\u003eMercury Marine sterndrive models with 4-inch exhaust outlets\u003c\/li\u003e\n\u003cli\u003eCompatible with many Alpha One, Bravo One, Bravo Two, and Bravo Three drives\u003c\/li\u003e\n\u003cli\u003eFits most MerCruiser V6 and V8 gasoline engines with transom exhaust systems\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eCommon Uses\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eReplacing broken, missing, or stuck exhaust flappers on sterndrive boats\u003c\/li\u003e\n\u003cli\u003ePreventing water from siphoning back into the engine via the exhaust system\u003c\/li\u003e\n\u003cli\u003eRestoring proper exhaust system function after flapper wear or failure\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number(s):\u003c\/strong\u003e 12644A1, 18-4457\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlapper Diameter:\u003c\/strong\u003e 4 inches\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Rubber flapper with stainless steel hinge\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMounting:\u003c\/strong\u003e Bolt-on\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e MerCruiser and Mercury sterndrive exhaust outlets\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eQ:\u003c\/strong\u003e Will this flapper fit a MerCruiser 5.0L Alpha One?\u003cstrong\u003e A:\u003c\/strong\u003e Yes, this 4-inch protector flapper is compatible with most MerCruiser Alpha One sterndrive models equipped with a 4-inch exhaust outlet, including 5.0L engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eQ:\u003c\/strong\u003e How do I know if my old flapper needs replacing?\u003cstrong\u003e A:\u003c\/strong\u003e If the flapper is cracked, missing, or does not close fully when the engine is off, it should be replaced to prevent water ingress into the exhaust system.\u003c\/p\u003e\u003cp\u003e\u003cem\u003eProduct appearance and specifications may vary slightly by batch. Compatibility may vary by serial number. Verify fitment before purchase.\u003c\/em\u003e\u003c\/p\u003e","brand":"DURAFORCE","offers":[{"title":"Default Title","offer_id":53676835078417,"sku":"ZZ2Y00919","price":39.59,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0250\/2446\/2929\/files\/57_19a21438-26f0-4a69-84d3-928f2a0738b6.jpg?v=1781579100","url":"https:\/\/www.duraforce.com\/products\/12644a1-18-4457-exhaust-4in-protector-flapper-for-mercruiser-mercury-sterndrive","provider":"DURAFORCE","version":"1.0","type":"link"}