The alcohol in the fuel has disolved your fuel lines, thus causing air leaks, which in turn causes an overly lean condition. Replace the fuel lines.
studmonkey
July 2009
Your chainsaw is 3.5hp - and sounds like the "high" carb setting is set too lean, turn it all the way in and then out 1.5 turns, start the saw and then adjust until it is revving fully and undo screw slightly until the saw revs just dip slightly or the engine burbles
steve
May 2009
Automatic Answer
While you wait for answers, we may have found some information which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix chainsaws.