{"product_id":"ngk-br6fs-spark-plug-4323","title":"NGK BR6FS SPARK PLUG - 4323","description":"\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0056\/9429\/2079\/files\/ngk_logo_1.png?v=1780608867\" alt=\"\"\u003e\u003c\/p\u003e\n\u003ch2\u003eNGK BR6FS Spark Plug – 4323\u003c\/h2\u003e\n\u003cp\u003eThe NGK BR6FS Spark Plug, stock number 4323, is a proven ignition replacement for a wide range of classic MerCruiser, Indmar, PCM, Crusader, Kodiak, Marine Power, and other GM-based marine engines. Built for dependable performance in demanding boating conditions, this resistor-style plug helps provide quick starting, smooth idle quality, clean acceleration, and consistent power under load.\u003c\/p\u003e\n\u003cp\u003eThe BR6FS uses a copper-core center electrode for efficient heat transfer and stable operating temperatures. Durable nickel-alloy firing surfaces provide reliable service life, while the built-in resistor helps reduce radio-frequency interference that can affect marine electronics. Corrosion-resistant shell plating adds another layer of protection in moisture-prone engine compartments.\u003c\/p\u003e\n\u003cp\u003eWorn or fouled plugs can contribute to hard starting, misfires, hesitation, increased fuel consumption, and loss of power. Replacing them during scheduled maintenance helps restore proper combustion and keeps older inboard and sterndrive engines running as intended.\u003c\/p\u003e\n\u003ch3\u003eSpark Plug Specifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eManufacturer: NGK\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003ePart Number: BR6FS\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eNGK Stock Number: 4323\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eType: Standard resistor spark plug\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eCenter Electrode Core: Copper\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eElectrode Material: Nickel\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eHeat Range: 6\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eThread Diameter: 14 mm\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eThread Reach: 11.2 mm\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eHex Size: 16 mm \/ 5\/8\"\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSpark Gap: 0.8 mm \/ .032\"\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eResistance: Approximately 5,000 ohms\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSold Individually\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCommon MerCruiser Engine Applications\u003c\/h3\u003e\n\u003cp\u003eThe NGK BR6FS \/ 4323 is specified for numerous MerCruiser gasoline engines, including select versions of:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 4.3L V6\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 4.3LX V6\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 5.0L \/ 305 CID V8\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 198\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 228\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 230\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 5.0L MIE\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 5.7L \/ 350 CID V8\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 330\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 340\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 350 MAG\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 350 MAG EFI\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 350 MAG MPI\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMerCruiser 400\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSelect MerCruiser 7.4L \/ 454 CID V8 engines\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eFor example, NGK specifically catalogs BR6FS for 1993–1996 MerCruiser 4.3LX engines through serial number 0F802999 and 2000–2006 350 MAG MPI applications through serial number 0F799999.\u003c\/p\u003e\n\u003ch3\u003eOther Marine Engine Applications\u003c\/h3\u003e\n\u003cp\u003eDepending on year and ignition configuration, the BR6FS is also commonly associated with engines such as:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eIndmar 3.0L GM\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eIndmar 4.3L V6 EFI\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eIndmar 5.0L V8\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eIndmar 5.7L V8 Carbureted\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eIndmar 5.7L V8 EFI\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eIndmar 5.7L TBI\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eIndmar 7.4L V8\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eIndmar 7.4L EFI\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eIndmar 8.2L V8\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eKodiak 4.3L V6\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eKodiak 7.4L V8\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSelect PCM GM-based engines\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSelect Crusader GM-based V8 engines\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSelect Marine Power GM-based engines\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCommon Inboard Boat Applications\u003c\/h3\u003e\n\u003cp\u003eCompatible GM-based engines were installed in many popular ski, wake, performance, and recreational boats. Depending on model year and original engine package, potential applications include:\u003c\/p\u003e\n\u003ch4\u003eSupra\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eSupra Comp\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSupra Sunsport\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSupra Saltare\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSupra Mariah\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSupra Pirata\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSelect early Supra Launch models\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eMoomba\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eMoomba Boomerang\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMoomba Outback\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMoomba Mobius\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSelect early Moomba direct-drive models\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eMalibu\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eMalibu Response\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMalibu Sunsetter\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMalibu Echelon\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMalibu Skier\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSelect Malibu Wakesetter models\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eMasterCraft\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eMasterCraft ProStar 190\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMasterCraft ProStar 205\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMasterCraft MariStar 200\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMasterCraft MariStar 225\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSelect early MasterCraft X-Series models\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCommon MerCruiser-Powered Boat Applications\u003c\/h3\u003e\n\u003cp\u003eThe BR6FS may also be found in compatible sterndrive engine packages installed in boats such as:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eSea Ray Bow Rider and Sundancer models\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eBayliner Capri and Ciera models\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eChaparral SSi and Signature models\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eFour Winns Horizon and Vista models\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eCrownline BR and CCR models\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eRinker Captiva and Fiesta Vee models\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eStingray bowriders\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eGlastron runabouts\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eLarson sport boats\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eRegal bowriders and cruisers\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eCobalt runabouts\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eBaja performance boats\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCross-Reference Numbers\u003c\/h3\u003e\n\u003cp\u003eCommon references associated with this application include:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eNGK BR6FS\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eNGK 4323\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMercury \/ Quicksilver 33-59571B\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eYamaha BR6-FS000-00-00\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eEvinrude \/ Johnson 0509573\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eEvinrude \/ Johnson 0503708\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAlways confirm an interchange number against the engine manufacturer's specifications before installation.\u003c\/p\u003e\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eGenuine NGK BR6FS marine spark plug\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eNGK stock number 4323\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eProven application in classic GM-based marine engines\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eCopper-core construction provides efficient heat dissipation\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eResistor design helps suppress radio-frequency interference\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eCorrosion-resistant shell plating\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSupports dependable starting and smooth acceleration\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eSuitable for select inboard and sterndrive engines\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eExcellent choice for routine tune-ups and seasonal maintenance\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eProven Ignition Performance for Classic Marine Engines\u003c\/h3\u003e\n\u003cp\u003eThe NGK BR6FS has been used in marine applications for decades and remains a popular replacement for many older GM-based power packages. Its straightforward copper-core design provides dependable ignition performance without unnecessary complexity, making it well suited for classic ski boats, wake boats, runabouts, cruisers, and performance boats.\u003c\/p\u003e\n\u003cp\u003eWhether you're servicing a MerCruiser 4.3LX, 5.0L, 350 MAG, an older Indmar-powered Supra or Moomba, or another compatible GM-based marine engine, the NGK BR6FS Spark Plug – 4323 provides reliable performance from a trusted ignition manufacturer.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFitment Note:\u003c\/strong\u003e Spark plug requirements can change within the same engine displacement based on year, ignition system, cylinder head, and serial-number range. Boat manufacturers also offered multiple engines in the same hull. Always verify \u003cstrong\u003eNGK BR6FS \/ stock #4323\u003c\/strong\u003e against the engine model, serial number, service manual, or original spark plug before ordering.\u003c\/p\u003e","brand":"Donovan Marine","offers":[{"title":"Default Title","offer_id":50254711030017,"sku":"41-BR6FS","price":4.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0056\/9429\/2079\/files\/321517_1.jpg?v=1788007080","url":"https:\/\/inboardpartshq.com\/products\/ngk-br6fs-spark-plug-4323","provider":"Inboard Parts HQ","version":"1.0","type":"link"}