When it dies does the fuel solenoid on the carb stick click if you turn off and on the ignition key. Do you have spark when it quits. It could also be a loose tip on the fuel solenoid, and you may have to remove the solenoid from the carb, and check the tip. Or the problem may not be any of the above.
If the suggestions don't help post the model numbers for the engine so we can see what you are looking at.
