Sat. off the coast of maine..all of a sudden...noise...bro..checks...motor still running...#4 cold...pulls wire...no change...but when he put wire back on...noise ..got better..sunday ...check #4 pull wire ...plug very loose..looked in hole ..looks ok.....took out #3 plug put it in #4 ..put #4 in # 3 ...but i don't dare do anything else ...'till i hear from you ...thanks 2.5 turns loose...i have had plugs go loose on a generator and aa air compressor...but not a boat motor...