My Stihl MS310 chainsaw was in the shop (a place that sells and works on Stihl saws) about 6 months ago with starting problems. The carb was replaced with new OEM carb and the it has started and ran fine since then - except 3 days ago when it wouldn't even fire. I checked the ignition spark first, and it was ok. The plug was also ok, but noticed that it was wet with fuel. I assumed the saw was flooded and left the plug out over night and even blue out the cylinder with air, all to no avail. I pulled the carb out and checked everything including main fuel jet and needle valve - all ok and carb was very clean. I used nylon fishing line to check all openings and jets. I reassembled the carb and saw fired one time, but didn't start. I didn't check the high and low speed valves since they were set at the shop and haven't changed, but maybe one of them could have become clogged however . Anyway, this definitely appears to be fuel related. I would have taken the saw back to the shop, but with the virus still very prevalent, I didn't want any public contact. Does anyone have any idea of what else might be causing this problem ?