{"product_id":"3854905-knock-sensor-assembly-for-volvo-penta-omc-jlm-marine","title":"3854905 Knock Sensor Assembly for Volvo Penta OMC | JLM Marine","description":"\u003ch2\u003eKnock Sensor Assembly – Fits Volvo Penta \u0026amp; OMC Cobra Sterndrive Marine Engines\u003c\/h2\u003e\n\n\u003cp\u003eThis aftermarket \u003cstrong\u003eMarine Knock Sensor Assembly\u003c\/strong\u003e is designed for \u003cstrong\u003eVolvo Penta stern drive\u003c\/strong\u003e and \u003cstrong\u003eOMC Cobra sterndrive marine engines\u003c\/strong\u003e. Engineered to detect engine knock and optimize ignition timing, this sensor ensures smooth performance and engine protection in marine applications.\u003c\/p\u003e\n\n\u003cp\u003eDirectly replaces OEM part numbers \u003cstrong\u003eVolvo Penta 3854905\u003c\/strong\u003e, \u003cstrong\u003eOMC Cobra 3854905\u003c\/strong\u003e, \u003cstrong\u003eSierra 18-7679\u003c\/strong\u003e, and \u003cstrong\u003eMallory 9-33504\u003c\/strong\u003e, providing a reliable and cost-effective solution for your sterndrive engine maintenance.\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eCompatible with Volvo Penta and OMC Cobra sterndrive engines\u003c\/li\u003e\n\u003cli\u003eDirect replacement for multiple OEM and aftermarket part numbers\u003c\/li\u003e\n\u003cli\u003ePrecision-engineered for marine engine knock detection\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\" style=\"border-collapse:collapse; width:100%;\"\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\u003eVolvo Penta\u003c\/td\u003e\n\u003ctd\u003e3854905\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOMC Cobra\u003c\/td\u003e\n\u003ctd\u003e3854905\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSierra\u003c\/td\u003e\n\u003ctd\u003e18-7679\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMallory\u003c\/td\u003e\n\u003ctd\u003e9-33504\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.\u003c\/p\u003e\n\n\u003cdiv style=\"overflow-x:auto;\"\u003e\n\u003ctable border=\"1\" cellpadding=\"8\" cellspacing=\"0\" style=\"border-collapse:collapse; width:100%;\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eEngine Type\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eVolvo Penta\u003c\/td\u003e\n\u003ctd\u003eStern Drive Marine Engines\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOMC\u003c\/td\u003e\n\u003ctd\u003eCobra Sterndrive Marine 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\" style=\"border-collapse:collapse; width:100%;\"\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\u003eType\u003c\/td\u003e\n\u003ctd\u003eMarine Knock Sensor\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEngine Type\u003c\/td\u003e\n\u003ctd\u003eOMC \/ Volvo Penta Sterndrive\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOEM Number\u003c\/td\u003e\n\u003ctd\u003e3854905\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\u003eThis package contains the following component:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"color:red;\"\u003e1 × Marine Knock Sensor\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 existing knock sensor on your Volvo Penta or OMC Cobra sterndrive engine block.\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 engine.\u003c\/li\u003e\n\u003cli\u003eClean the mounting surface on the engine block to ensure proper contact and seal.\u003c\/li\u003e\n\u003cli\u003eInstall the new knock sensor by threading it into the mounting hole hand-tight first.\u003c\/li\u003e\n\u003cli\u003eTorque the sensor to the manufacturer's recommended specification (typically 15–20 ft-lbs; consult your service manual).\u003c\/li\u003e\n\u003cli\u003eReconnect the electrical connector to the new knock sensor, ensuring a secure fit.\u003c\/li\u003e\n\u003cli\u003eReconnect the negative battery cable.\u003c\/li\u003e\n\u003cli\u003eStart the engine and verify proper operation with no warning lights or performance issues.\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 your engine is a Volvo Penta stern drive or OMC Cobra sterndrive model. Cross-reference your current part number with those listed (3854905, Sierra 18-7679, Mallory 9-33504) to confirm compatibility.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What are the signs that my knock sensor needs replacement?\u003c\/strong\u003e\u003cbr\u003e\nA: Common symptoms include engine pinging or knocking under load, reduced power, poor fuel economy, check engine light illumination, or stored knock sensor fault codes in the engine computer.\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 last many years, but should be replaced immediately if fault codes appear or if engine knocking occurs. Inspect during routine engine servicing or if performance issues arise.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Can I install this sensor myself or do I need a mechanic?\u003c\/strong\u003e\u003cbr\u003e\nA: Installation is straightforward for those with basic mechanical skills and tools. However, proper torque specifications and electrical connector care are critical, so professional installation is recommended if you're unsure.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Is this an OEM part or 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","brand":"JLM Marine","offers":[{"title":"Default Title","offer_id":51981005127993,"sku":"23SE185","price":30.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0885\/0433\/6697\/files\/12_a21b35a7-82bc-4a02-995a-b1b3069dd7f9.jpg?v=1772414376","url":"https:\/\/jlmmarine.com\/es\/products\/3854905-knock-sensor-assembly-for-volvo-penta-omc-jlm-marine","provider":"JLM Marine Boat Parts Limited","version":"1.0","type":"link"}