I have a Stihl O21 chain saw about 5 years old, light usage. Last fall it
developed problems starting and it got so once I would get it running, it
would work until I shut it off then there was no getting it restarted until
it cooled. I took it to the repair shop and the guy said that the head was
warped and that it was not worth repairing. I talked to a different guy and
he told me that if I changed the gas/oil mix for 1 bottle of oil to a gallon
of gas, to 2 bottles of oil to a gallon of gas , I might get some use out of
it. I tried this, this weeked and the thing works like a champ. Starts every
time, hot or cold. My question now is, can this last or will it eventually
sieze up? Can someone explain to me what is going on, why the heavier oil
mix would make it run?

Thanks.