B6S Spark Plug | NGK 3510Premium NGK spark plugs are known for their reliable performance and superior anti-fouling characteristics. NGK spark plug B6S Stock number 3510 14mm x 1.25mm thread Gasket seat Standard type Gap .028 in. (0.7mm) 13/16 in. hex Replaces Universal 273276 Replaces Volvo Penta 876123 Replaces Mercury/Mercruiser 33-813469