We lost the fire in two cylinders at the end of the year last year. It would run on two cylinders. but not all 4. This year we diagnosed the problem to the power pack. We drained the fuel and replaced with fresh. New plugs. Upon cranking the engine it backfired and emits a lot of blue smoke. Engine will not start. I realize it is a two cycle but the smoke seems excessive to me. All four plugs are firing and getting wet. What to look for now?