... black C. gold metal customer brand A7tc spark plug copper, alloy, platinum, iridium goldCeramic white or ... CONTAMINATION AND DIRT.2. SET THE SPARK PLUG ONTO THE CYLINDER HEADAND, TIGHTENNING AND KEEP THE ... SPARK PLUG TO TURN 90°~180°. PLEASE KEEP 30 ... TIMES BEFORE.3, MAKE SURE SPARK PLUG RIGHT INSTALLATION. SPARK PLUG HOUSING BREAKS IF TOO TIGHT WHILE ...