Mac 3214 chainsaw stalls after running, adjustments??

I have a Mac 3214 chainsaw. It runs for a little while, 5-10 minutes, then dies and will not restart. It has a new plug, new fuel, etc.
There are three accessible turn screws for the saw.
A large one, T and two smaller ones in the housing,
H and L.
The saw isn't even worth a trip to the shop, and it's never ever run right. For years it wouldn't start, then for some reason began to start OK but only runs for a few minutes then dies out and won't restart until it has cooled off completely. Very frustrating and worthless on a ranch. However I don't have the money for a new saw so how can I adjust this thing to get it to work and earn it's keep?

Tom D in Grass Valley CA
November 2009