Start with a pressure, vacuum, and volume check of the pump. "Wheelbarrow" troubleshooting doesn't work very well- - - -start with a wheelbarrow full of new parts and keep changing them until something fixes it!
First test- - - -disconnect the fuel line at the carburetor and direct the fuel into a 1-qt. container like an oil bottle. Start the engine and let it idle. A good pump will produce 1 pint of fuel in 30 seconds. If the volume is low, test the pressure- - - -deadhead the fuel line into a gauge, idle the engine and check the pressure. You should see 3-5 PSI, and the pressure should remain for several seconds after shutdown. Last test- - - -connect a vacuum gauge to the pump inlet and run the engine. You should see 10-15 inches of vacuum with a few seconds of residual vacuum after shutdown. If the pump passes all these tests, check the line back to the tank, including the flex line, for air leaks. You should have at least 80% of the pump vacuum at the tank outlet.
Jerry
