Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Does the fuel line go straight from the tank to the carb with only the fuel filter between it?
The gas will only flow for so long until the carb bowl fills up and then it will stop until the fuel level drops and the float opens the needle valve and allows more fuel in it.
It should remain full. I think I would replace the fuel line to eliminate a line that is sucking air to start with.