Last fall I limped around the lake with an engine that had no power. I had driven the boat 1 season on a new ignition module and now had just installed new coils and spark plugs. I gapped the plugs to 0.040 as I have always done with each plug change. Last week I went at the problem. I installed new carb kits, carefully setting float height. The engine started right off, seemed to warm up ok, but when I put it to full power it missed a bit and sounded just like it did last fall. It lead me to suspect that one cylinder was not firing. I examined the spark plugs and noticed that the lower cylinder plug had a black film on it. I put a spark plug tester on each cylinder, and while in the dark, observed good spark to each. What I also noticed on the lower cylinder, was that sparks were jumping thru the spark plug boot to ground on the engine head. There were about 3 arcs that were each easily jumping about 1/2" or more. I changed the plugs with no change. I had the engine compression tested last year. Compression was 142 psi on both cylinders. I need help with this problem.
