{"product_id":"8m0021043-fuel-water-sensor-for-mercury-marine-jlm-marine","title":"8M0021043 Fuel \u0026 Water Sensor for Mercury Marine | JLM Marine","description":"\u003cbody\u003e\n\n\n\u003cmeta charset=\"UTF-8\"\u003e\n\n\n\n\u003ch2\u003eFuel \u0026amp; Water Sensor for Mercury Marine 75-400HP Outboards\u003c\/h2\u003e\n\n\u003cp\u003eThis \u003cstrong\u003eFuel and Water Sensor\u003c\/strong\u003e is designed for Mercury Marine outboard engines ranging from \u003cstrong\u003e75HP to 400HP\u003c\/strong\u003e. Engineered to detect water contamination in your fuel system, this sensor helps protect your engine from damage and ensures reliable performance on the water.\u003c\/p\u003e\n\n\u003cp\u003eThis aftermarket replacement directly replaces Mercury Marine part numbers \u003cstrong\u003e8M0021043\u003c\/strong\u003e, \u003cstrong\u003e8M0157779\u003c\/strong\u003e, and \u003cstrong\u003e889330\u003c\/strong\u003e, providing a cost-effective solution for maintaining your outboard's fuel system integrity.\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eDirect replacement for Mercury Marine OEM sensors\u003c\/li\u003e\n\u003cli\u003eDetects water contamination in fuel system\u003c\/li\u003e\n\u003cli\u003eCompatible with 75-400HP Mercury outboards\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Cross-Reference\u003c\/h2\u003e\n\n\u003cp\u003eUse this table to confirm equivalent part numbers across OEM and aftermarket brands.\u003c\/p\u003e\n\n\u003ctable border=\"1\" cellpadding=\"8\" cellspacing=\"0\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003ePart Number\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury Marine\u003c\/td\u003e\n\u003ctd\u003e8M0021043\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury Marine\u003c\/td\u003e\n\u003ctd\u003e8M0157779\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury Marine\u003c\/td\u003e\n\u003ctd\u003e889330\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eCompatible Engine Models\u003c\/h2\u003e\n\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\" target=\"_blank\" rel=\"nofollow noopener\"\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\" target=\"_blank\" rel=\"nofollow noopener\"\u003eMercury Parts Diagrams \u0026amp; Catalog\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003cdiv style=\"overflow-x:auto;\"\u003e\n\u003ctable border=\"1\" cellpadding=\"8\" cellspacing=\"0\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eRated HP\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury Marine\u003c\/td\u003e\n\u003ctd\u003e75HP - 400HP\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\n\u003ctable border=\"1\" cellpadding=\"8\" cellspacing=\"0\"\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\u003ePart Type\u003c\/td\u003e\n\u003ctd\u003eFuel and Water Sensor\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eFuel System Water Detection\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible Brand\u003c\/td\u003e\n\u003ctd\u003eMercury Marine\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHorsepower Range\u003c\/td\u003e\n\u003ctd\u003e75HP - 400HP\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003ePackage Contents\u003c\/h2\u003e\n\n\u003cp\u003eYour package includes:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"color:red;\"\u003e\u003cstrong\u003e1 × Fuel and Water Sensor\u003c\/strong\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Guide\u003c\/h2\u003e\n\n\u003col\u003e\n\u003cli\u003eDisconnect the battery negative terminal to ensure safety during installation.\u003c\/li\u003e\n\u003cli\u003eLocate the existing fuel and water sensor on your Mercury outboard fuel system.\u003c\/li\u003e\n\u003cli\u003eDisconnect the electrical connector from the old sensor by pressing the release tab.\u003c\/li\u003e\n\u003cli\u003eUse an appropriate wrench to carefully unscrew the old sensor from the fuel filter assembly.\u003c\/li\u003e\n\u003cli\u003eInspect the mounting threads and clean any debris or residue from the mounting area.\u003c\/li\u003e\n\u003cli\u003eHand-thread the new fuel and water sensor into the fuel filter assembly to avoid cross-threading.\u003c\/li\u003e\n\u003cli\u003eTighten the sensor to the manufacturer's recommended torque specification using a torque wrench.\u003c\/li\u003e\n\u003cli\u003eReconnect the electrical connector to the new sensor, ensuring it clicks securely into place.\u003c\/li\u003e\n\u003cli\u003eReconnect the battery negative terminal.\u003c\/li\u003e\n\u003cli\u003eTurn the ignition key to the \"ON\" position and check that the sensor warning light functions properly.\u003c\/li\u003e\n\u003cli\u003eInspect for any fuel leaks around the sensor mounting area before starting the engine.\u003c\/li\u003e\n\u003cli\u003eStart the engine and monitor the system for proper operation and no warning indicators.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: How do I confirm this sensor fits my Mercury outboard?\u003c\/strong\u003e\u003cbr\u003e\nA: This sensor is designed for Mercury Marine outboards rated between 75HP and 400HP. Check your engine's horsepower rating and verify the original part number (8M0021043, 8M0157779, or 889330) against your existing sensor to ensure compatibility.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What are the signs that my fuel and water sensor needs replacement?\u003c\/strong\u003e\u003cbr\u003e\nA: Common symptoms include a persistent water-in-fuel warning light, engine misfiring or hesitation, difficulty starting, or poor performance. If you notice any of these issues, inspect and test your fuel and water sensor.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: How often should I replace the fuel and water sensor?\u003c\/strong\u003e\u003cbr\u003e\nA: The sensor typically does not require regular replacement unless it fails or becomes damaged. However, it should be inspected during routine maintenance and replaced if it shows signs of corrosion, physical damage, or fails diagnostic testing.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Can I install this sensor myself, or do I need a professional?\u003c\/strong\u003e\u003cbr\u003e\nA: If you have basic mechanical skills and the proper tools, you can install this sensor yourself by following the installation guide. However, professional installation is recommended to ensure proper torque, electrical connections, and system safety.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: OEM vs. Aftermarket?\u003c\/strong\u003e\u003cbr\u003e\nA: This 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\n\u003cp\u003e\u003cstrong\u003eQ: How fast do you ship and how much does it cost?\u003c\/strong\u003e\u003cbr\u003e\nA: We 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\n\u003cp\u003e\u003cstrong\u003eQ: What is your warranty and return policy?\u003c\/strong\u003e\u003cbr\u003e\nA: This 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\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\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\n\n\u003c\/body\u003e","brand":"JLM Marine","offers":[{"title":"Default Title","offer_id":51980999524665,"sku":"23FS379","price":15.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0885\/0433\/6697\/files\/12_10872526-4021-44ba-ac88-57e60b772a00.jpg?v=1772414111","url":"https:\/\/jlmmarine.com\/products\/8m0021043-fuel-water-sensor-for-mercury-marine-jlm-marine","provider":"JLM Marine Boat Parts Limited","version":"1.0","type":"link"}