{"product_id":"champion-rn9yc-spark-plug-415-4-pack-marine-inboard-sterndrive-24-rn9yc","title":"Champion RN9YC Spark Plug | #415 | 4-Pack | Marine Inboard \u0026 Sterndrive","description":"\u003ch2\u003eHotter Heat Range Spark Plug for Marine Inboard and Sterndrive Engines — 4-Pack.\u003c\/h2\u003e\u003cp\u003eThe Champion RN9YC is a projected-tip, resistor-type spark plug for marine inboard and sterndrive engines. Part number 415, the RN9YC runs one heat range hotter than the \u003ca href=\"\/products\/champion-rn12yc-spark-plug-404-4-pack-mercruiser-sterndrive-marine-inboard-24-rn12yc\"\u003eChampion RN12YC #404\u003c\/a\u003e — making it the correct choice for engines that run cooler or at lower average RPM, where a hotter plug helps burn off carbon deposits and maintain a clean electrode.\u003c\/p\u003e\u003cp\u003eThe YC-suffix design features a projected tip for improved ignitability and a built-in resistor to suppress radio frequency interference. Sold in a 4-pack (Champion part 44165). Always verify fitment against your engine's owner's manual or Champion application guide before ordering.\u003c\/p\u003e\u003ch3\u003eKey Features\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eChampion RN9YC spark plug — 4-pack (Champion #415)\u003c\/li\u003e\n\u003cli\u003eHotter heat range than the RN12YC — for cooler-running or lower-RPM marine inboard applications\u003c\/li\u003e\n\u003cli\u003eProjected tip for improved ignitability and combustion efficiency\u003c\/li\u003e\n\u003cli\u003eBuilt-in resistor suppresses radio frequency interference (RFI)\u003c\/li\u003e\n\u003cli\u003eCopper core electrode for reliable heat transfer and consistent spark\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eCompatible Applications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMerCruiser sterndrive engines specifying Champion RN9YC or equivalent\u003c\/li\u003e\n\u003cli\u003eGM\/Chevrolet V8-based marine inboard engines specifying RN9YC or equivalent\u003c\/li\u003e\n\u003cli\u003eFord V8-based marine inboard engines specifying RN9YC or equivalent\u003c\/li\u003e\n\u003cli\u003eCooler-running or lower-average-RPM marine inboard engines where a hotter plug is specified\u003c\/li\u003e\n\u003cli\u003eAny application cross-referencing Champion #415 or part 44165\u003c\/li\u003e\n\u003cli\u003eVerify fitment using your engine's owner's manual or the Champion spark plug application guide\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eParts Desk Insights\u003c\/h3\u003e\u003cp\u003eThe RN9YC is the hotter sibling of the \u003ca href=\"\/products\/champion-rn12yc-spark-plug-404-4-pack-mercruiser-sterndrive-marine-inboard-24-rn12yc\"\u003eChampion RN12YC #404\u003c\/a\u003e — if your engine specifies the RN9YC, use the RN9YC. A hotter plug is appropriate when your engine runs cool and you're seeing carbon fouling on the electrode. If your engine specifies the RN12YC, don't substitute the RN9YC thinking a hotter plug is always better — a plug that's too hot for the application can cause pre-ignition and engine damage.\u003c\/p\u003e\u003cp\u003eFor other ignition components for MerCruiser and sterndrive engines, browse our \u003ca href=\"\/collections\/ignition-components\"\u003eIgnition Components\u003c\/a\u003e collection. For NGK alternatives in marine inboard applications, see the \u003ca href=\"\/products\/ngk-spark-plugs-bpr6es-7131-4-pk-41-bpr6es\"\u003eNGK BPR6ES\u003c\/a\u003e.\u003c\/p\u003e","brand":"LNS","offers":[{"title":"Default Title","offer_id":51250815598628,"sku":"24-RN9YC","price":8.78,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/24-L76V_d5b4d951-711d-4a64-99cf-7e6bcd17ce12.jpg?v=1786510610","url":"https:\/\/marisolmarine.com\/products\/champion-rn9yc-spark-plug-415-4-pack-marine-inboard-sterndrive-24-rn9yc","provider":"Marisol Marine Company","version":"1.0","type":"link"}