Small Engines (Lawn Mowers, etc.): B&S 20 hp Twin Cylinder, safety switches, keyswitch


Question
Starts, then stalls, all filters have been changed, checked safety switches. I am getting back blow of gas out of the carburetor. Any suggestions?

Answer
To start, please find the model numbers off of the engine, or at least tell me if it is an ohv, intek, vangard, or any other info.

It stalls when you put it in gear?  Or will start and stall without
doing anything?  Does it start when the keyswitch is cranking, then die when the key returns to the run position?  Can you find the model numbers of the tractor?  It should be under the seat.
Has this been running at all this year?  It ran fine when last parked?  Anything happen or was done to the tractor that might be
relevant?

Does it stall when you are moving?  When stalling, will quickly pulling out the choke make it run any longer?
When it stalls, will it restart immediately then stall again?  Or does it have to sit a while before it will restart?

Sorry about the questions, but they will help me focus more quickly on the problem.
Thanks,

Fish