{"product_id":"mercury-ngk-itr4a15-4-33-8m0204739","title":"Mercury – NGK ITR4A-15 Laser Iridium Spark Plug | MerCruiser V6 \u0026amp; V8 Series | Iridium \u0026amp; Copper Core | 8M0204739","description":"\u003ch2\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMercury – NGK ITR4A-15 Laser Iridium Spark Plug | MerCruiser V6 \u0026amp; V8 Series | Iridium \u0026amp; Copper Core | 8M0204739\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eOverview\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e There’s nothing quite like that first turn of the key when the engine fires instantly — clean, sharp, and confident. It sets the tone for the entire day on the water. \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eWhether you’re easing away from the dock or opening up the throttle across open chop, knowing your ignition system is rock-solid gives you peace of mind that’s hard to beat. This Mercury Marine part is built for that very feeling. With each spark delivering smooth, steady power, you’ll feel the difference long before you reach cruising speed.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eKey Features\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eNGK ITR4A-15 Laser Iridium spark plug designed for long-lasting, high-performance ignition\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eFine-wire Iridium center electrode for slow wear, stable idle, and crisp throttle response\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eCopper core for efficient heat dissipation and consistent combustion\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eTrivalent metal plating offers enhanced corrosion resistance in marine environments\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eRibbed suppressor seal prevents flashover and reduces misfires\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMercury Marine part number 8M0204739\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003ePre-gapped to manufacturer specifications\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eEngine \u0026amp; Boat Compatibility\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eFits select MerCruiser engines, including four-point-three-liter, five-liter, five-point-seven-liter, and six-point-two-liter models\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eSuitable for sterndrive and inboard applications using NGK ITR4A-15 plugs\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eIdeal for cruisers, sport boats, bowriders, cabin cruisers, and performance-oriented recreational boats\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eDesigned for engines where smooth idle, strong acceleration, and dependable ignition are essential\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003ePerformance \u0026amp; Practical Benefits\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Ignition performance shapes how your entire day on the water feels. These Laser Iridium plugs deliver a tight, clean spark that keeps your MerCruiser running \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003esmooth\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e from idle to wide-open throttle. The fine-wire Iridium tip requires less voltage to fire, which means more consistent combustion, improved fuel efficiency, and better throttle response — especially noticeable when accelerating hard or trimming the bow up in rough water.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eThe copper core draws heat away efficiently, reducing the chance of fouling during long idle sessions or frequent stop-and-go operation around marinas. You’ll notice the engine holds a steadier idle, responds with a smoother push, and maintains strong power across the \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003efull\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e RPM range. \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eAnd because\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e of the high corrosion resistance \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eof the trivalent plating\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e, these plugs hold up well even in saltwater environments, making removal easier and more predictable after a full season of use.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eReplacing the whole set restores uniform performance across all cylinders, giving your engine that balanced, “just-tuned” feel that makes the boat run tighter and cleaner than before.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eWhy Buy OEM\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e When you’re running a MerCruiser, the ignition system deserves nothing less than the engineering it \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ewas built around\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e. Genuine Mercury Marine parts ensure the heat range, gap, electrode design, and materials match your engine exactly. Aftermarket plugs might resemble the real thing, but internal differences can lead to misfires, reduced power, or uneven wear — problems that only show up when you’re miles from the dock.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eOEM plugs deliver consistent performance, longer life, and better protection against marine conditions. It’s the kind of practical advice any seasoned boater would offer: use the spark plugs Mercury intended, and your engine will reward you with smoother starts, cleaner performance, and fewer headaches.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eFAQ\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ1: Which engines does the NGK ITR4A-15 Spark Plug 8M0204739 fit?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e It fits select MerCruiser four-point-three-liter, five-liter, five-point-seven-liter, and six-point-two-liter engines.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ2: What makes these spark plugs better than aftermarket versions?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e The Laser Iridium tip, copper core, trivalent plating, and Mercury-approved specs offer superior durability, corrosion resistance, and consistent ignition.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ3: How do I confirm it’s the right plug for my setup?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Check your owner’s manual or existing plu\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eg. If your engine calls for NGK ITR4A-15 or part number 8M0204739, you’re good to go.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ4: Can these be used in both saltwater and freshwater boats?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Yes — the corrosion-resistant plating and ceramic insulator are built for all marine environments.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ5: Is installation straightforward?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Absolutely. With a standard spark plug socket and careful threading, they install smoothly and seat securely.\u003c\/span\u003e\u003c\/p\u003e","brand":"Mercury","offers":[{"title":"Default Title","offer_id":46940551348515,"sku":"33-8M0204739","price":19.25,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0783\/7410\/9475\/files\/8M0204739_2.jpg?v=1761308286","url":"https:\/\/partsvu.com\/en-ca\/products\/mercury-ngk-itr4a15-4-33-8m0204739","provider":"PartsVu","version":"1.0","type":"link"}