Could very well be an air leak. That would compound an icing problem as well. After it dies can you hold the throttle wide open on the pistol grip with one hand, lay the saw's bar on a log with the other (chain break off) and "yo yo" start the saw? If you can. Run it for a few minutes without letting it die. It'll probably smoke and be a bit boggy, but run it fir a few minutes staying on the pipe as much as you can. Then after a few minutes. Let it die. Then, while staying outside, hold the saw upright with the grip pointing up and the tip on the ground. Let it sit for a minute or two. If it fires up after two or three minutes. You've got icing conditions and need to somehow block 1/2 of you air fan on the suction side. Duck tape over the outside of half your starter cover works great!