After rebuilding pump had ski out today ran amazing for 3 hours and almost a full tank ski cut off 3 times started right back up thought I had water in some electrical from all the waves and spins anyways started bogging down and thought carb issue .got home cranked it up and started for 5sec, took plugs out and middle cylinder was smoking cranked over and 1 and 3 I could see pistons moving middle cylinder has no movement worst case ? Cost and is it any harder then rebuilding a suburb engine which I have done with a blown head gasket ? Runs on premix and wave eater clips any idea what made it happen ?