Small Engines (Lawn Mowers, etc.): tecumseh 17hp ohv, murray riding mower, stale gas

Question
i have a murray riding mower with a 17hp ohv tecumseh engine model number 42539a. it runs only if you pour gas in carburator. what is causing this

Answer
There are 4 possibilities.

1: there is old stale gas in the carb and fuel tank.  Drain the carb, and the fuel that is in the tank and see if this works.

2: your fuel shutoff solenoid is not getting power or is bad and is not allowing fuel to flow through.

3: Your fuel is shut off or no fuel in tank

4: your carb is dirty and needs to be disassembled and cleaned to allow the fuel to flow through so it continues to run.

By pouring gas into the carb, the tractor will run until it burns the fuel you have poured into it.  Once its gone the engine stops.

Hope this helps.