Small Engines (Lawn Mowers, etc.): Stihl Chainsaw stalls, fuel tank, fuel lines

Question
I have a Stihl chainsaw that stalls if you let off the throttle.  It will run fine if you give it gas, but will stall right away once you let off.  Could it just be bad gas or a bad spark plug?

Thanks,
Todd

Answer
Probably it's the carburetor stopped up a little.  The idle circuit in the carb is probably not flowing fuel.  The solution is to soak the carb in cleaner for an hour or so and then reassemble with a new carb kit.  We replace fuel lines and filters when rebuilding carburetors and also clean out the fuel tank.