{"product_id":"806612t-knock-sensor-for-mercury-mercruiser-omc-volvo-penta-jlm-marine","title":"806612T Knock Sensor for Mercury Mercruiser OMC Volvo Penta | JLM Marine","description":"\u003ch2\u003eKnock Sensor for Mercury Mercruiser OMC Volvo Penta | JLM Marine\u003c\/h2\u003e\n\n\u003cp\u003eThis \u003cstrong\u003eknock sensor\u003c\/strong\u003e is engineered to fit \u003cstrong\u003eGM Small Block marine engines\u003c\/strong\u003e including Mercury Mercruiser, OMC, Volvo Penta, PCM, Marine Power, and Crusader. Designed for GM 305 (5.0L), 350 (5.7L), and 377 (6.2L) V8 engines, this sensor plays a critical role in engine protection by detecting pre-ignition or detonation and signaling the ECM to retard timing, preventing internal damage to pistons and valves.\u003c\/p\u003e\n\n\u003cp\u003eThis sensor directly replaces OEM part number \u003cstrong\u003e806612T\u003c\/strong\u003e and crosses with Crusader R020027, Sierra 18-7677, and Volvo Penta 3850357. It installs in the water port located in the middle of the engine block, just above the oil pan on GM Small Block engines.\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eFits GM 305 5.0L, 350 5.7L, and 377 6.2L small block V8 marine engines\u003c\/li\u003e\n\u003cli\u003eDetects pre-ignition\/detonation to prevent engine damage\u003c\/li\u003e\n\u003cli\u003eInstalls in the water port above the oil pan\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 Mercruiser\u003c\/td\u003e\n\u003ctd\u003e806612T\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVolvo Penta\u003c\/td\u003e\n\u003ctd\u003e3850357\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCrusader\u003c\/td\u003e\n\u003ctd\u003eR020027\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSierra\u003c\/td\u003e\n\u003ctd\u003e18-7677\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\" rel=\"nofollow noopener\" target=\"_blank\"\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\" rel=\"nofollow noopener\" target=\"_blank\"\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\u003eEngine Model\u003c\/th\u003e\n\u003cth\u003eNotes\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eMercury Mercruiser\u003c\/td\u003e\n\u003ctd\u003eGM 305 5.0L, 350 5.7L, 377 6.2L Small Block V8\u003c\/td\u003e\n\u003ctd\u003eInstalled in water port above oil pan\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOMC\u003c\/td\u003e\n\u003ctd\u003eGM Small Block Marine Engines\u003c\/td\u003e\n\u003ctd\u003eCompatible with V8 configurations\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVolvo Penta\u003c\/td\u003e\n\u003ctd\u003eGM Small Block Marine Engines\u003c\/td\u003e\n\u003ctd\u003e5.0L and 5.7L applications\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePCM\u003c\/td\u003e\n\u003ctd\u003eGM Small Block Marine Engines\u003c\/td\u003e\n\u003ctd\u003eV8 small block engines\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMarine Power\u003c\/td\u003e\n\u003ctd\u003eGM Small Block Marine Engines\u003c\/td\u003e\n\u003ctd\u003eV8 small block engines\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCrusader\u003c\/td\u003e\n\u003ctd\u003eGM Small Block Marine Engines\u003c\/td\u003e\n\u003ctd\u003eV8 small block engines\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\u003eOEM Number\u003c\/td\u003e\n\u003ctd\u003e806612T\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFunction\u003c\/td\u003e\n\u003ctd\u003eDetects pre-ignition\/detonation and signals ECM to retard timing\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInstallation Location\u003c\/td\u003e\n\u003ctd\u003eWater port in middle of block, above oil pan\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEngine Type\u003c\/td\u003e\n\u003ctd\u003eGM Small Block V8 (305, 350, 377 cu. in.)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCross Reference\u003c\/td\u003e\n\u003ctd\u003eCrusader R020027, Sierra 18-7677, Volvo Penta 3850357\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\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"color:red;\"\u003e1 × Knock Sensor (806612T)\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 negative battery cable to ensure safety during installation.\u003c\/li\u003e\n\u003cli\u003eLocate the water port in the middle of the engine block, just above the oil pan.\u003c\/li\u003e\n\u003cli\u003eDisconnect the electrical connector from the old knock sensor.\u003c\/li\u003e\n\u003cli\u003eUsing an appropriate wrench or socket, carefully unscrew and remove the old knock sensor from the water port.\u003c\/li\u003e\n\u003cli\u003eInspect the mounting area and threads; clean any debris or corrosion if present.\u003c\/li\u003e\n\u003cli\u003eApply a small amount of anti-seize compound to the threads of the new knock sensor (avoid getting compound on the sensor tip).\u003c\/li\u003e\n\u003cli\u003eHand-thread the new knock sensor into the water port to prevent cross-threading.\u003c\/li\u003e\n\u003cli\u003eTighten the sensor to the manufacturer's specified torque (typically 10-15 ft-lbs; consult your service manual).\u003c\/li\u003e\n\u003cli\u003eReconnect the electrical connector to the new knock sensor until it clicks securely.\u003c\/li\u003e\n\u003cli\u003eReconnect the negative battery cable.\u003c\/li\u003e\n\u003cli\u003eStart the engine and check for proper operation; verify there are no warning lights or fault codes.\u003c\/li\u003e\n\u003cli\u003eInspect for any leaks around the sensor installation point and re-tighten if necessary.\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 knock sensor fits my engine?\u003c\/strong\u003e\u003cbr\u003e\nA: Verify that your engine is a GM Small Block V8 (305, 350, or 377 cu. in.) used in Mercury Mercruiser, OMC, Volvo Penta, PCM, Marine Power, or Crusader applications. Cross-reference your current part number with 806612T, Volvo Penta 3850357, Crusader R020027, or Sierra 18-7677.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What are the symptoms of a failing knock sensor?\u003c\/strong\u003e\u003cbr\u003e\nA: Common signs include engine pinging or knocking under load, reduced power, poor fuel economy, illuminated check engine light, or fault codes related to knock sensor circuit. A faulty sensor cannot properly signal the ECM to retard timing, risking internal engine damage.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Where exactly does this sensor install on my engine?\u003c\/strong\u003e\u003cbr\u003e\nA: This knock sensor installs in the water port located in the middle of the engine block, just above the oil pan on GM Small Block engines. It threads into the block and connects via an electrical harness.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: How often should I replace the knock sensor?\u003c\/strong\u003e\u003cbr\u003e\nA: Knock sensors typically do not have a fixed replacement interval and are replaced only when they fail or show symptoms. However, if you experience persistent knocking, poor performance, or related fault codes, test and replace the sensor as needed.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Is this an OEM or aftermarket part?\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","brand":"JLM Marine","offers":[{"title":"Default Title","offer_id":51966113579321,"sku":"21SR010","price":18.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0885\/0433\/6697\/files\/Ud03d9381d59c4522b4406d07875eb80fe.webp?v=1771923849","url":"https:\/\/jlmmarine.com\/products\/806612t-knock-sensor-for-mercury-mercruiser-omc-volvo-penta-jlm-marine","provider":"JLM Marine Boat Parts Limited","version":"1.0","type":"link"}