{"product_id":"sierra-18-97353-carb-kit-mercury-20-50-hp-outboard","title":"Sierra 18-97353 Carb Kit, Mercury 20-50 HP Outboard","description":"\u003cp class=\"nvn-hero\"\u003eThe Sierra 18-97353 carburetor rebuild kit gets your Mercury 20 to 50 HP outboard running clean again. It packs the fuel inlet needle valve, needle seat, carburetor bowl and flange gaskets, internal O-rings, and gaskets you need for a full carb refresh. If your motor's hard to start, loading up, or weeping fuel at idle, this is the fix.\u003c\/p\u003e\n\n\u003cdiv class=\"nvn-description\"\u003e\n\u003cp\u003eA carburetor rebuild is one of those jobs that sounds intimidating and turns out to be a good weekend project. The Sierra 18-97353 kit gives you the wear parts that actually go bad inside a Mercury 20 to 50 HP outboard carburetor. You get the fuel inlet needle valve, the needle seat, the carburetor bowl gasket, the flange gasket, the internal O-rings, and the small gaskets that seal everything up. Everything's in one box, so you're not chasing individual parts at three different counters.\u003c\/p\u003e\n\u003cp\u003eSo how do you know it's time? The usual tells are hard starting after the boat's been sitting, a motor that loads up and bogs at idle, or fuel weeping from the bowl when the engine's warm. Ethanol is usually the culprit. Modern pump gas draws moisture and slowly breaks down the rubber inside the carb, so the internal O-rings swell and the needle stops sealing. A couple of seasons of that and the carb just won't meter fuel the way it should. Dropping in fresh wear parts brings the fuel system back to spec without the cost of a whole new carburetor.\u003c\/p\u003e\n\u003cp\u003eThis kit covers the 20 to 50 HP Mercury outboard range, which spans a lot of years and a few different carb castings. Before you order, pull your carburetor number and confirm it matches. Some of the older 1980s-era motors used a slightly different needle valve, and matching the carb number up front saves you a second trip. If you're running a 35 HP Jet model, plan on a main jet adjustment after the rebuild to get the mixture dialed back in.\u003c\/p\u003e\n\u003cp\u003eWorth being clear on what this is and what it isn't. It's a wear-parts and gasket kit, the pieces that degrade and seal. It's not a complete carburetor and it doesn't include the float or the main jets, so you'll reuse those from your existing carb after a good cleaning. Blow the passages out with carb cleaner and compressed air while you've got it apart. Fresh gaskets on a carb full of old varnish won't fix a lean stumble, so the cleaning and the rebuild go hand in hand.\u003c\/p\u003e\n\u003cp\u003eOn the bench, take your time with the needle and seat. On some 40 HP carbs the new seat doesn't drop in perfectly flush right out of the box, and a light dressing of the casting gets it seated square. Don't force it. A seat that sits crooked will leak no matter how clean the rest of the job is. When you set the fuel inlet needle, cycle the throttle around twenty times before that first start, especially on the 25 HP. That frees the needle so it doesn't stick closed and starve the motor on the initial crank.\u003c\/p\u003e\n\u003cp\u003eThe gaskets reward a little patience too. The flange gasket on the 30 HP tears easily if you're wrestling the carb back onto the intake, so wipe a thin film of grease on it to hold it in place while you line up the studs. For the bowl gasket, snug the bowl screws evenly and bring them to about 45 inch-pounds. On the 50 HP that torque matters. Too loose and it'll seep at idle. When you're done, a quick soapy-water test around the bowl seam will show you any bubbles before you ever splash the boat.\u003c\/p\u003e\n\u003cp\u003eOne more thing worth knowing. Bigger motors in this range often run more than one carburetor, so if you're pulling one to rebuild it, it's usually smart to do the whole bank at the same time. The carbs age together, and matching fresh parts across all of them keeps the cylinders pulling even fuel. It's the difference between a motor that idles smooth and one that hunts.\u003c\/p\u003e\n\u003cp\u003eSierra has been building marine replacement parts for decades, and their gaskets and O-rings meet or exceed the original equipment they replace. That means the same fit, the same sealing, and the same durability you'd expect from the parts that came off the motor, at a price that makes a rebuild worth doing. Keep a kit on the shelf if you run an older Mercury. Carbs don't usually pick a convenient time to act up, and having the parts on hand means you're back on the water instead of waiting on an order.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul class=\"nvn-features\"\u003e\n  \u003cli\u003eFits Mercury Marine 20 to 50 HP outboard engines, covering a wide span of model years and carburetor castings\u003c\/li\u003e\n  \u003cli\u003eIncludes the fuel inlet needle valve and needle seat, the two parts most responsible for a carb that floods or won't start\u003c\/li\u003e\n  \u003cli\u003eCarburetor bowl gasket and flange gasket seal the two joints most likely to weep fuel\u003c\/li\u003e\n  \u003cli\u003eInternal O-rings replace the ethanol-swollen rubber that causes hard starting and a rough idle\u003c\/li\u003e\n  \u003cli\u003eComplete gasket and wear-part set in one box, so a full rebuild doesn't turn into a parts hunt\u003c\/li\u003e\n  \u003cli\u003eSierra parts meet or exceed the original equipment they replace for OEM fit and sealing\u003c\/li\u003e\n  \u003cli\u003eManufacturer part number 18-97353 for easy cross-reference against your carburetor number\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cdiv class=\"nvn-trust\"\u003e\n  \u003ch2\u003eWhy Buy from NVN Marine\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eAuthorized Sierra Marine reseller, full manufacturer warranty\u003c\/li\u003e\n    \u003cli\u003eNMEA member and ABYC certified, advice from real boat techs\u003c\/li\u003e\n    \u003cli\u003eSame-day shipping before 3 PM ET on in-stock items\u003c\/li\u003e\n    \u003cli\u003eNY headquarters and Fort Lauderdale flagship retail store\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cdiv class=\"nvn-faq\"\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat engines does the Sierra 18-97353 kit fit?\u003c\/summary\u003e\n    \u003cp\u003eIt fits Mercury Marine outboards from 20 to 50 HP. That range covers several years and a few carburetor castings, so pull your carb number and confirm it matches before ordering.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat's included in the kit?\u003c\/summary\u003e\n    \u003cp\u003eYou get the fuel inlet needle valve, needle seat, carburetor bowl gasket, flange gasket, internal O-rings, and the internal gaskets. It's the wear-and-seal set for a full carb refresh.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDoes it include the float or main jets?\u003c\/summary\u003e\n    \u003cp\u003eNo. This is a wear-parts and gasket kit. You'll reuse your existing float and jets after cleaning the carb body, so plan on carb cleaner and a compressed-air pass while it's apart.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow do I know my carburetor needs a rebuild?\u003c\/summary\u003e\n    \u003cp\u003eCommon signs are hard starting after sitting, a motor that bogs or loads up at idle, and fuel weeping from the bowl when warm. Ethanol breaks down the internal rubber over a couple of seasons, and that's usually what you're chasing.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eMy 35 HP is a Jet model. Anything different?\u003c\/summary\u003e\n    \u003cp\u003eThe kit still fits, but plan on a main jet adjustment after the rebuild to get the fuel mixture dialed back in on a Jet motor.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eThe new needle seat won't sit flush. What now?\u003c\/summary\u003e\n    \u003cp\u003eOn some 40 HP carbs the seat casting needs a light dressing so the seat sits square. Take your time and don't force it. A crooked seat will leak no matter how clean the rest of the job is.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow tight should the bowl screws be?\u003c\/summary\u003e\n    \u003cp\u003eSnug them evenly to about 45 inch-pounds, especially on the 50 HP. Too loose and the bowl gasket seeps at idle. A soapy-water test around the seam afterward shows any bubbles before you launch.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eThe motor won't start right after the rebuild. Why?\u003c\/summary\u003e\n    \u003cp\u003eCycle the throttle around twenty times before the first start, especially on the 25 HP. That frees the fuel inlet needle so it doesn't stick closed and starve the motor on the initial crank.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eI have a multi-carb motor. Should I rebuild all of them?\u003c\/summary\u003e\n    \u003cp\u003eUsually yes. The carbs age together, so refreshing the whole bank at once keeps the cylinders pulling even fuel and the idle smooth.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable class=\"nvn-specs\"\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003cth\u003eTitle\u003c\/th\u003e\n\u003ctd\u003eSierra 18-97353 Carburetor Rebuild Kit for Mercury Marine 20 to 50 HP Outboard Engines\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eSierra Marine\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eManufacturer Part Number\u003c\/th\u003e\n\u003ctd\u003e18-97353\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUPC\u003c\/th\u003e\n\u003ctd\u003e808282386979\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eProduct Type\u003c\/th\u003e\n\u003ctd\u003eCarburetor Rebuild Kit\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eFits Engine Make\u003c\/th\u003e\n\u003ctd\u003eMercury Marine\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eEngine Horsepower Range\u003c\/th\u003e\n\u003ctd\u003e20 to 50 HP\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eFuel Inlet Needle Valve\u003c\/th\u003e\n\u003ctd\u003eIncluded\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eNeedle Seat\u003c\/th\u003e\n\u003ctd\u003eIncluded\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eCarburetor Bowl Gasket\u003c\/th\u003e\n\u003ctd\u003eIncluded\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eFlange Gasket\u003c\/th\u003e\n\u003ctd\u003eIncluded\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eInternal O-Rings\u003c\/th\u003e\n\u003ctd\u003eIncluded\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eInternal Gaskets\u003c\/th\u003e\n\u003ctd\u003eIncluded\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n    \"@context\": \"https:\/\/schema.org\",\n    \"@type\": \"FAQPage\",\n    \"mainEntity\": [\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What engines does the Sierra 18-97353 kit fit?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It fits Mercury Marine outboards from 20 to 50 HP. That range covers several years and a few carburetor castings, so pull your carb number and confirm it matches before ordering.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What's included in the kit?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"You get the fuel inlet needle valve, needle seat, carburetor bowl gasket, flange gasket, internal O-rings, and the internal gaskets. It's the wear-and-seal set for a full carb refresh.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Does it include the float or main jets?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"No. This is a wear-parts and gasket kit. You'll reuse your existing float and jets after cleaning the carb body, so plan on carb cleaner and a compressed-air pass while it's apart.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How do I know my carburetor needs a rebuild?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Common signs are hard starting after sitting, a motor that bogs or loads up at idle, and fuel weeping from the bowl when warm. Ethanol breaks down the internal rubber over a couple of seasons, and that's usually what you're chasing.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"My 35 HP is a Jet model. Anything different?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The kit still fits, but plan on a main jet adjustment after the rebuild to get the fuel mixture dialed back in on a Jet motor.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"The new needle seat won't sit flush. What now?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"On some 40 HP carbs the seat casting needs a light dressing so the seat sits square. Take your time and don't force it. A crooked seat will leak no matter how clean the rest of the job is.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How tight should the bowl screws be?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Snug them evenly to about 45 inch-pounds, especially on the 50 HP. Too loose and the bowl gasket seeps at idle. A soapy-water test around the seam afterward shows any bubbles before you launch.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"The motor won't start right after the rebuild. Why?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Cycle the throttle around twenty times before the first start, especially on the 25 HP. That frees the fuel inlet needle so it doesn't stick closed and starve the motor on the initial crank.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"I have a multi-carb motor. Should I rebuild all of them?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Usually yes. The carbs age together, so refreshing the whole bank at once keeps the cylinders pulling even fuel and the idle smooth.\"\n            }\n        }\n    ]\n}\n\u003c\/script\u003e\n","brand":"Sierra Marine","offers":[{"title":"Default Title","offer_id":45063136510045,"sku":"2008699","price":79.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0299\/7266\/0317\/files\/ImageServerAPI_18082289-ec96-48b2-a9df-2f44e3c1a474.png?v=1789586506","url":"https:\/\/nvnmarine.com\/products\/sierra-18-97353-carb-kit-mercury-20-50-hp-outboard","provider":"NVN Marine","version":"1.0","type":"link"}