{"product_id":"mercury-ac-41-983-4-33-863622001","title":"Mercury – ACDelco GM Original Equipment 41-983 Double Platinum Spark Plug | MerCruiser Big Block Ignition Series | Double Platinum Finish | 8M0129146","description":"\u003ch1\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMercury – ACDelco GM Original Equipment 41-983 Double Platinum Spark Plug | MerCruiser Big Block Ignition Series | Double Platinum Finish | 8M0129146\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h1\u003e\n\u003ch2\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eOverview\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eThere’s a special kind of frustration when a big sterndrive engine doesn’t feel crisp. It might still run, but it doesn’t feel clean. Starts take a little longer, idle gets a touch rough, and you catch yourself listening harder than you should. Spark plugs are small parts with a big voice, and when they’re fresh and correct for the engine, you can feel the difference right away.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eThis Mercury Marine part is the plug you install when you want your MerCruiser to fire the way it \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ewas meant\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e to. It’s steady, reliable, and built for the real rhythm of boating—long cruises, hot engine bays, and plenty of time under load. Put in the \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eright\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e plugs, and the whole boat feels calmer.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eKey Features\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eDouble platinum spark plug designed for consistent ignition and long service life\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eBuilt by ACDelco as a GM original equipment style plug\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eNickel alloy tip and copper core construction to support durability and dependable performance\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eRibbed\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e suppressor seal design helps provide a secure seal and stable operation\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eRecommended approach: replace spark plugs rather than cleaning used plugs\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eBest practice: replace all engine plugs at the same time for balanced performance\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eFits applications including MerCruiser 496 MAG and 496 High Output, and MerCruiser inboard 8.1 liter and 8.1 liter High Output engines\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMercury Marine part number 8M0129146\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eEngine \u0026amp; Boat Compatibility\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMerCruiser 496 MAG engines\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMerCruiser 496 High Output engines\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMerCruiser inboard 8.1 liter engines\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMerCruiser inboard 8.1 liter High Output engines\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eCommon on cruisers, performance runabouts, offshore-leaning sport boats, and larger family boats with \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ebig\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e block power\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003ePerformance \u0026amp; Practical Benefits\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eFresh spark plugs don’t just help the engine start—they \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ehelp\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e it run the way you remember. With the \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eright\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e plug in place, ignition tends to feel more consistent. Idle smooths out. Throttle response feels cleaner. You get that steady, confident pull when you ease into the power, instead of a slight hesitation that makes you second-guess the day.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eThe \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003edouble platinum\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e design is a practical choice for marine use because \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eit’s built\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e to \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ehold up over time\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e.\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Marine engines often spend \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003elong\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e periods at a steady load, then shift into idle, then back to load again. \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eThat cycling\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e can be hard on ignition components. \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eA \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eplug designed for durability\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e helps keep performance stable, not just \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003efor\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e the first trip after install, but \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eacross\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e the season.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eInstallation is straightforward for most boat owners who are comfortable with routine maintenance. \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eThe key is \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ebeing consistent\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e: use the correct plug for your engine, gap it according to your manual, and swap the \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003efull\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e set so everything \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eis firing\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e evenly.\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e When you do it right, the engine feels tighter and more predictable, which is \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eexactly\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e what you want when you’re a long way from the ramp.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eWhy Buy OEM\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eIgnition parts are not the place to experiment. A genuine Mercury Marine part like this \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eis chosen\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e to match the engine’s needs—heat range, design, and overall fitment. That means fewer misfires, fewer weird running issues, and less time chasing problems \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ethat start with\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e the wrong plug.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eAftermarket options can vary, even when they look similar on paper. OEM keeps it simple: install the plug your engine is designed to run, and you’ll get performance that feels right the first time. It’s practical advice, but it’s true—especially with big block MerCruiser power.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eFAQ Section\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ1: Which Mercury engines or systems does the Double Platinum Spark Plug fit?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eIt’s intended for MerCruiser 496 MAG and 496 High Output, plus MerCruiser inboard \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e8.1 liter\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e and \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e8.1 liter\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e High Output engines.\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Always confirm with your engine owner’s manual.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ2: What makes this part different from aftermarket alternatives?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eIt’s a Mercury Marine part built \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003earound\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e GM original equipment style \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003edesign\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e with a \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003edouble platinum\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e configuration for consistent ignition and durability.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ3: \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eHow do I know if\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e this \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eis\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e the correct replacement for my setup?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Check your engine model and verify the recommended spark plug in your manual, then match the part number to 8M0129146.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ4: Can this be used in both saltwater and freshwater applications?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Yes. Spark plugs serve the ignition system in any environment. \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eGood maintenance and \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ecorrosion control\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e habits help in saltwater.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ5: Is installation straightforward for most boat owners?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e For many owners, yes. Replace the \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003efull\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e set, follow the manual for gap and torque, and you’ll usually feel a smoother, steadier engine right away.\u003c\/span\u003e\u003c\/p\u003e","brand":"Mercury","offers":[{"title":"Default Title","offer_id":46940551741731,"sku":"33-863622001","price":20.67,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0783\/7410\/9475\/files\/PV485898_8.jpg?v=1698813230","url":"https:\/\/partsvu.com\/en-ca\/products\/mercury-ac-41-983-4-33-863622001","provider":"PartsVu","version":"1.0","type":"link"}