Mercury - NGK ILFR6GE Laser Iridium Spark Plug Ignition Component Steel and Ceramic 889246Q39. Overview. There's something reassuring about a spark plug you never have to second-guess. The NGK ILFR6GE Laser Iridium plug has that kind of quiet reliability - the kind you only notice after a season of clean starts, smooth idle, and none of the hesitation that can make your stomach drop when you're loading the boat for an early run. It delivers that crisp fire you need whether you're easing out of t