tiller doesn't stay running

Mark, I,m guessing this unit has an 8hp B&S vertical engine on it. There could be a number of things causing your problem. I always like to start with the basics. A compression and ignition check would give us some clue, however you said it starts and runs for a minute would indicate that it has compression and ignition (at least initially). You could use an in-line ignition tester to make sure its not losing spark. If this is an older unit, it may still have points and condenser. If this is the case I would install an electronic ignition conversion. Next thing I would look at is the carb. If this unit has been setting the fuel system may be in need of an overhaul. Joe