{"product_id":"392-889925-8m0178581-3859078-ignition-coil-for-mercruiser-volvo-8-1l-496-mag-jlm-marine","title":"392-889925 8M0178581 3859078 Ignition Coil for MerCruiser Volvo 8.1L 496 MAG | JLM Marine","description":"\u003ch2\u003eIgnition Coil for MerCruiser Volvo 8.1L 496 MAG – High-Performance Replacement\u003c\/h2\u003e\n\n\u003cp\u003eThis aftermarket ignition coil is engineered to fit \u003cstrong\u003eMerCruiser 8.1L 496 MAG\u003c\/strong\u003e series marine gasoline engines (2001 and newer) and \u003cstrong\u003eVolvo Penta\u003c\/strong\u003e equivalent models. Designed to meet OEM specifications, it delivers reliable spark energy for consistent engine performance in demanding marine environments.\u003c\/p\u003e\n\n\u003cp\u003eThis coil directly replaces \u003cstrong\u003eMerCruiser 392-889925\u003c\/strong\u003e and \u003cstrong\u003e8M0178581\u003c\/strong\u003e, as well as \u003cstrong\u003eVolvo Penta 3859078\u003c\/strong\u003e and \u003cstrong\u003eSierra 18-7493\u003c\/strong\u003e, ensuring broad cross-compatibility with original equipment and popular aftermarket brands.\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003eDirect replacement for multiple OEM and aftermarket part numbers\u003c\/li\u003e\n\u003cli\u003eCompatible with MerCruiser 8.1L \/ 496 MAG marine gasoline engines (2001-Up)\u003c\/li\u003e\n\u003cli\u003eSingle ignition coil unit included\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\u003cth\u003eNotes\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003e392-889925\u003c\/td\u003e\n\u003ctd\u003eSuperseded by 8M0178581\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003e8M0178581\u003c\/td\u003e\n\u003ctd\u003eCurrent OEM number\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVolvo Penta\u003c\/td\u003e\n\u003ctd\u003e3859078\u003c\/td\u003e\n\u003ctd\u003eOEM equivalent\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSierra\u003c\/td\u003e\n\u003ctd\u003e18-7493\u003c\/td\u003e\n\u003ctd\u003eAftermarket replacement\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\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003cth\u003eModel\u003c\/th\u003e\n\u003cth\u003eYears\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\u003eMerCruiser\u003c\/td\u003e\n\u003ctd\u003e8.1L (496 MAG Series)\u003c\/td\u003e\n\u003ctd\u003e2001-Up\u003c\/td\u003e\n\u003ctd\u003eGM marine gasoline engines, Design II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVolvo Penta\u003c\/td\u003e\n\u003ctd\u003e8.1L equivalent models\u003c\/td\u003e\n\u003ctd\u003e2001-Up\u003c\/td\u003e\n\u003ctd\u003eCompatible with Volvo 8.1L 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\"\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\u003eProduct Type\u003c\/td\u003e\n\u003ctd\u003eIgnition Coil\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEngine Type\u003c\/td\u003e\n\u003ctd\u003eMarine Gasoline\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDisplacement\u003c\/td\u003e\n\u003ctd\u003e8.1L \/ 496 cu. in.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eApplication\u003c\/td\u003e\n\u003ctd\u003eMerCruiser 496 MAG, Volvo Penta 8.1L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDesign\u003c\/td\u003e\n\u003ctd\u003eDesign II\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFitment Year Range\u003c\/td\u003e\n\u003ctd\u003e2001 and newer\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× Ignition Coil\u003c\/strong\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cem\u003eThe package contains all parts shown in the product images.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch2\u003eInstallation Guide\u003c\/h2\u003e\n\n\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003eDisconnect the battery\u003c\/strong\u003e negative terminal to prevent electrical shock or short circuits during installation.\u003c\/li\u003e\n\u003cli\u003eLocate the faulty ignition coil on your engine block; refer to your service manual or OEM diagrams for exact positioning.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDisconnect the electrical connector\u003c\/strong\u003e from the old coil by pressing the release tab and gently pulling it away.\u003c\/li\u003e\n\u003cli\u003eRemove the mounting bolt(s) securing the coil to the engine using the appropriate socket or wrench.\u003c\/li\u003e\n\u003cli\u003eCarefully lift the old coil off the spark plug boot; twist gently if resistance is felt to avoid damaging the boot.\u003c\/li\u003e\n\u003cli\u003eInspect the spark plug boot for cracks, corrosion, or wear; replace if necessary to ensure proper connection.\u003c\/li\u003e\n\u003cli\u003ePosition the new ignition coil over the spark plug and press down firmly until fully seated.\u003c\/li\u003e\n\u003cli\u003eReinstall the mounting bolt(s) and torque to manufacturer specifications (typically 8–12 ft-lbs; consult your manual).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReconnect the electrical connector\u003c\/strong\u003e by pushing it onto the coil terminal until you hear or feel a click.\u003c\/li\u003e\n\u003cli\u003eRepeat the process for any additional coils if replacing multiple units.\u003c\/li\u003e\n\u003cli\u003eReconnect the battery negative terminal and start the engine to verify proper operation and smooth idle.\u003c\/li\u003e\n\u003cli\u003eCheck for misfires, rough running, or warning lights; if issues persist, verify all connections and consult a marine technician.\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 ignition coil fits my MerCruiser or Volvo engine?\u003c\/strong\u003e\u003cbr\u003e\nA: Verify your engine is an 8.1L (496 MAG) series built in 2001 or later. Cross-reference the OEM part numbers listed (392-889925, 8M0178581, or Volvo 3859078) with your current coil or service manual to ensure compatibility.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What are the signs that my ignition coil is failing?\u003c\/strong\u003e\u003cbr\u003e\nA: Common symptoms include engine misfires, rough idling, loss of power under load, difficulty starting, increased fuel consumption, or a check-engine light. If you experience these issues, test the coil resistance with a multimeter or swap with a known good coil to isolate the problem.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: How often should I replace my ignition coils?\u003c\/strong\u003e\u003cbr\u003e\nA: Ignition coils typically last 3–5 years or 300–500 engine hours, depending on operating conditions. Replace coils if you notice performance issues, or proactively during major tune-ups to prevent unexpected failures on the water.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Can I install this coil myself, or do I need a professional?\u003c\/strong\u003e\u003cbr\u003e\nA: Installation is straightforward for those with basic mechanical skills and tools. However, if you are unfamiliar with marine electrical systems or lack the proper torque specifications, professional installation is recommended to ensure safety and optimal performance.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Is this an OEM part or an aftermarket replacement?\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":51981021446457,"sku":"24IC489","price":41.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0885\/0433\/6697\/files\/12_95586dfa-e07e-48d4-9e7c-0db4bae348fe.jpg?v=1772414710","url":"https:\/\/jlmmarine.com\/es\/products\/392-889925-8m0178581-3859078-ignition-coil-for-mercruiser-volvo-8-1l-496-mag-jlm-marine","provider":"JLM Marine Boat Parts Limited","version":"1.0","type":"link"}