usually the air fuel mixture is alittle lean when a saw does this. Alot of things causes this, adjustment screw vibrates just enough to make the saw run badly, differents is air temp. and densty of the air, and dirt (microscope) particially blocking the needle valve and seat.

If you are familiar with these carb. I would remove air fuel mixture (hi and lo) (note how many revelations from all the way in) spray some carb cleaner down the hole to hopefully blow out and dirt. once you got the saw running and it still stalls out. I would then try to adjust the Hi air mixture screw out 1/16 or 1/8" turn. If it don't help by 1/4", you make have a weak diaphramn, if so your carb will have to be dissassembled, cleaned and new gaskets and diaphramn installed most likely.

Too much for you? Just start it and spray some carb. cleaner directly down the carb while it's running at a high speed. Then try to adjust the hi screw to see if you can enrichen the mixture some which should help the stalling problem.