The engine runs great the first 1 or 2 times taking it out but let it set and it will foul the plugs. Like today taking it out with new plugs again after the first time of it fouling the plugs and it runs great, stopped and fished for a hr cranked it up with no problem, moved and fished for another hr and again crank it up with no problem. Ran it down the river for a while then pulled back in at the dock and sit there about 15-20 mins talking, but when I went to crank it to pull it on the trail it fouled the plugs. Oil injection has been disconnected and I premix the oil/gas and run 100% gas. As I said it had new plugs, wires and the carbs have been rebuilt and float settings have been rechecked after the first time it fouled the plugs. New gas lines from the tanks to the carbs and new thermostats any ideas?