Mercruiser 470 / 3.7 1985 - 1987 S/N 779810. I have had no running issues lately, but decided to change the cap, rotor, wires and plugs. (never did the wires since I owned the boat) Upon removing the plugs, which I changed the spring of 2011, I found them burning in this fashion: What story do they tell? The plug on the left was in the front of the motor(#1) and the right plug was in the back fo the motor (#4). Thanks for your time. It is a very smooth and powerful motor. I have done a tone of stuff and am hoping I'm not on my to a head gasket repair:facepalm:.