Thanks guys, You're right, the plug is badly fouled and I thought that may be causing the misfire but I couldn't figure out how it would fire with the wire disconnected. Thanks for the explanation. Randall. Anyway, the plugs are Champions and only have about 300 miles them so I'll clean up the fouled one see what happens.
Oh, one more question: fouled #4 plug after only 300 miles, rear carb too rich??