{"product_id":"sierra-18-0550-plug-off-cap-1-1-4-in-31-8mm-replaces-omc-909830-evinrude-johnson-3852476","title":"Sierra 18-0550 Plug Off Cap, Replaces OMC 909830, 1-1\/4 Inch","description":"\u003cp\u003eThe Sierra 18-0550 Plug Off Cap is a plastic plug cap used to seal an unused port on marine exhaust manifold applications. It is sized for a 1-1\/4 inch (31.8mm) opening and is molded in white plastic for durability in the marine engine compartment environment. This cap is designed as a direct aftermarket equivalent to OMC 909830, meeting or exceeding the performance of the original equipment part it replaces.\u003c\/p\u003e\u003cp\u003eThe 18-0550 is a simple, purpose-built component: a single plug that presses or threads into place to close off an exhaust manifold port that is not being used in a given engine configuration, keeping the cooling and exhaust system sealed properly. Because it is interchangeable with several OEM and aftermarket cross-reference numbers, it can be used to service a range of OMC, Evinrude\/Johnson, GLM, and Mallory-numbered applications that call for this same 1-1\/4 inch plug cap. Each unit ships as a single cap ready to install.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Sierra\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 18-0550\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Name:\u003c\/strong\u003e Plug Off Cap\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Plastic\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor:\u003c\/strong\u003e White\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInside Diameter:\u003c\/strong\u003e 1-1\/4 inch (31.8mm)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.08 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eQuantity:\u003c\/strong\u003e 1 plug off cap per unit\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross Reference:\u003c\/strong\u003e GLM 22280, Evinrude\/Johnson 909830, 3852476, Mallory 9-42721, OMC 909830\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cp\u003eFits applications calling for a 1-1\/4 inch (31.8mm) exhaust manifold plug off cap, including those originally equipped with OMC 909830 or 3852476.\u003c\/p\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eGLM 22280\u003c\/li\u003e\n\u003cli\u003eEvinrude\/Johnson 909830\u003c\/li\u003e\n\u003cli\u003e3852476\u003c\/li\u003e\n\u003cli\u003eMallory 9-42721\u003c\/li\u003e\n\u003cli\u003eOMC 909830\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat is the Sierra 18-0550 Plug Off Cap used for?\u003c\/strong\u003e The Sierra 18-0550 is a plastic plug cap that seals an unused 1-1\/4 inch exhaust manifold port on applicable marine engines, keeping the exhaust and cooling passages closed off where a fitting is not installed.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat size is the Sierra 18-0550 plug off cap?\u003c\/strong\u003e It has a 1-1\/4 inch (31.8mm) inside diameter, sized to fit the port opening it is designed to seal.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-0550 replace OMC 909830?\u003c\/strong\u003e Yes, the Sierra 18-0550 is interchangeable with OMC 909830 and is built to meet or exceed the performance of that original equipment part.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat other part numbers cross-reference to the Sierra 18-0550?\u003c\/strong\u003e The 18-0550 is interchangeable with GLM 22280, Evinrude\/Johnson 909830, Evinrude\/Johnson 3852476, Mallory 9-42721, and OMC 909830 and 3852476.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat material is the Sierra 18-0550 plug off cap made from?\u003c\/strong\u003e It is made of white plastic, a lightweight material suited to sealing exhaust manifold ports in the marine engine compartment.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-0550 genuine OEM or aftermarket?\u003c\/strong\u003e It is a Sierra aftermarket part manufactured to meet or exceed the specifications of the original equipment part it replaces, such as OMC 909830.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow many plug off caps come in one Sierra 18-0550 package?\u003c\/strong\u003e One Sierra 18-0550 plug off cap is included per unit.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-0550 plug off cap weigh?\u003c\/strong\u003e The 18-0550 weighs 0.08 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan the 18-0550 be used in place of a Mallory 9-42721 cap?\u003c\/strong\u003e Yes, the Mallory 9-42721 is one of the cross-reference numbers the Sierra 18-0550 is interchangeable with.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-0550 threaded or a press-fit plug?\u003c\/strong\u003e The 18-0550 is a plug off cap sized to a 1-1\/4 inch (31.8mm) opening; specific thread or press-fit installation details beyond that sizing are not specified.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988078506203,"sku":"SIE-18-0550","price":10.66,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/Untitled-1__72359.1771572386.500.750.jpg?v=1785188038","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-0550-plug-off-cap-1-1-4-in-31-8mm-replaces-omc-909830-evinrude-johnson-3852476","provider":"Good Vibes Marina","version":"1.0","type":"link"}