{"product_id":"merc-3","title":"Mercury Carburetor Float Bowl O-Ring 25-16259","description":"\u003ch2\u003eMercury Carburetor Float Bowl O-Ring 25-16259\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003ePart Number:\u003c\/strong\u003e 25-16259 (short ref: 16259)\u003cbr\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Mercury \/ Quicksilver\u003cbr\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Carburetor Float Bowl O-Ring (OEM)\u003cbr\u003e\n\u003cstrong\u003eSystem:\u003c\/strong\u003e Outboard Fuel System \/ Carburetor\u003cbr\u003e\n\u003cstrong\u003ePosition:\u003c\/strong\u003e Between carburetor body and float bowl\u003cbr\u003e\n\u003cstrong\u003eQuantity Required:\u003c\/strong\u003e 1 per carburetor\u003cbr\u003e\n\u003cstrong\u003eGTIN \/ UPC:\u003c\/strong\u003e 745061117433\u003cbr\u003e\n\u003cstrong\u003eApproximate Weight:\u003c\/strong\u003e 5 g\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch3\u003eWhat This Part Does\u003c\/h3\u003e\n\u003cp\u003eThe 25-16259 is a genuine OEM O-ring that seals the float bowl to the carburetor body on selected small Mercury and Mariner 2-stroke outboard engines. It prevents fuel from leaking at the bowl joint. The O-ring sits in the float-bowl sealing groove and is replaced whenever the bowl is removed for service or the seal shows deterioration.\u003c\/p\u003e\n\n\u003ch3\u003eCompatible Applications\u003c\/h3\u003e\n\u003cp\u003eConfirm your engine horsepower, serial number, and carburetor model against the Mercury carburetor diagram before ordering. Mercury used several different carburetor and bowl-seal designs across similar horsepower ranges — do not select this O-ring by diameter or appearance alone.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eMercury \/ Mariner 4 HP 2-stroke outboard\u003c\/li\u003e\n\u003cli\u003eMercury \/ Mariner 5 HP 2-stroke outboard\u003c\/li\u003e\n\u003cli\u003eMercury \/ Mariner 6 HP 2-stroke outboard\u003c\/li\u003e\n\u003cli\u003eMercury \/ Mariner 8 HP 2-stroke outboard\u003c\/li\u003e\n\u003cli\u003eMercury \/ Mariner 9.8 HP 2-stroke outboard\u003c\/li\u003e\n\u003cli\u003eMercury \/ Mariner 9.9 HP 2-stroke outboard\u003c\/li\u003e\n\u003cli\u003eSelected SeaPro and international variants within these horsepower ranges\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSerial Number Notice\u003c\/h3\u003e\n\u003cp\u003eMercury used multiple carburetor assemblies across these horsepower ranges. Always confirm by engine serial number and the correct carburetor float-bowl diagram. Nearby fuel-system seals in the same assembly may look similar but carry different Mercury part numbers — match by part number, not appearance.\u003c\/p\u003e\n\n\u003ch3\u003eDiagram Position\u003c\/h3\u003e\n\u003cp\u003eParts diagrams show 25-16259 installed between the carburetor body and float bowl, used alongside:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eFloat bowl 803691T01 (later applications)\u003c\/li\u003e\n\u003cli\u003eFloat-bowl screws 162601 (qty 4)\u003c\/li\u003e\n\u003cli\u003eDrain-screw gasket 16262\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhen to Replace\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eFloat bowl is removed for any carburetor service (replace as a matter of course)\u003c\/li\u003e\n\u003cli\u003eFuel leakage is visible around the bowl-to-carburetor joint\u003c\/li\u003e\n\u003cli\u003eO-ring is flattened, permanently compressed, or no longer sealing\u003c\/li\u003e\n\u003cli\u003eRubber has hardened, cracked, or become brittle\u003c\/li\u003e\n\u003cli\u003eSeal is cut, swollen, or distorted on inspection\u003c\/li\u003e\n\u003cli\u003eCarburetor cleaning reveals deterioration of the existing seal\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eInstallation Notes\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eClean the float-bowl sealing groove and carburetor mating surface thoroughly before installing the new O-ring\u003c\/li\u003e\n\u003cli\u003eSeat the O-ring evenly in the groove — do not twist, stretch, or pinch it during installation\u003c\/li\u003e\n\u003cli\u003eLightly lubricate the O-ring with clean fuel or a compatible O-ring lubricant before assembly\u003c\/li\u003e\n\u003cli\u003eConfirm the bowl is fully and evenly seated before tightening the bowl screws\u003c\/li\u003e\n\u003cli\u003eAfter reassembly, run the engine and inspect for fuel leaks at the bowl joint\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003ePart Number Cross-Reference\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCurrent OEM:\u003c\/strong\u003e 25-16259\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShort Reference:\u003c\/strong\u003e 16259\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical FAQ\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Can I use a generic O-ring from a hardware store?\u003c\/strong\u003e\u003cbr\u003eA: Not recommended for fuel-system applications. Carburetor O-rings must be compatible with gasoline and ethanol-blended fuels. A generic O-ring may swell, degrade, or fail quickly in contact with marine fuel. Use the OEM part for reliable sealing.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: How many O-rings does my carburetor need?\u003c\/strong\u003e\u003cbr\u003eA: 1 per carburetor at the float bowl position. Confirm your carburetor diagram — the same assembly may include additional seals (such as the drain-screw gasket 16262) that should be replaced at the same time.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: My engine has the same HP as the list but the O-ring doesn’t look right — why?\u003c\/strong\u003e\u003cbr\u003eA: Mercury used more than one carburetor design within the same horsepower range. If the O-ring size or shape doesn’t match, confirm your engine serial number and the carburetor model number against the parts diagram before ordering.\u003c\/p\u003e\n\n\u003ch3\u003eParts Desk Insights\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eBest use case:\u003c\/strong\u003e Order 25-16259 whenever the float bowl is coming off a small Mercury or Mariner 2-stroke carburetor — it’s a low-cost seal that eliminates the risk of reassembling with a compromised O-ring. Most experienced technicians replace it automatically during any carburetor clean or service.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCommon issues:\u003c\/strong\u003e The most frequent mistake is ordering by O-ring size rather than part number — Mercury used different bowl seal designs across similar HP engines, so appearance is not a reliable guide. A second common issue is missing the drain-screw gasket (16262) during the same service — both seals are in the same assembly and worth replacing together.\u003c\/p\u003e\n\n\u003ch3\u003eRelated Parts\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131646390308\"\u003eSierra Marine Fuel Pump 18-7278 — Mercury \/ Mariner 4–15 HP 2-Stroke\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"MERC","offers":[{"title":"Default Title","offer_id":51324675915812,"sku":"16259","price":29.54,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/4eb6f1f1-6c42-42aa-8682-9d11cee45e38.png?v=1788661915","url":"https:\/\/marisolmarine.com\/products\/merc-3","provider":"Marisol Marine Company","version":"1.0","type":"link"}