This is an older Stihl FS80. Right up front I want to say the engine was submerged in a flood. I emptied out the cylinder and it ran fine for about three tanks of gas. Then.. nothing. I noticed that the ignition wire was a little melted and then the replacing started. New coil and plug=strong spark. Engine appeared flooded new carb and fuel lines. The rings were brittle and breaking+new rings. I had a new muffler laying around so new muffler. The issue seems to be that the piston is not opening up the carb intake on the down stroke. When the rings were off it had full movement. Does this mean the cylinder is warped? Any suggestions?