I've got a 05 yam 4 stroke that I ran about 3 times a week for two monthes.. When I first got it I changed plugs. Even after the change it ran fine just idle wasn't terrible but not perfect either. I took the motor off to paint the boat and put it on after only sitting one week, no spark. Took plugs out and they are black and one seemed to have a liquid on it.. Being my first boat I don't know what this would be and If it's normal for spark plugs to go that fast. Any info is helpful thank you