There are 1-way check valves inside the pump, inlet and outlet. Use a pressure/vacuum gauge to test it. With the pump output dead-headed into the gauge, idle the engine for a few seconds, running on the fuel in the carburetor. It should produce 3-5 PSI and hold the pressure for a few seconds after shutdown. Then go to the input side and attach the gauge instead of the line from the tank. You should see about 10 inches of vacuum and the check valve should hold the reading for 10-15 seconds. The pump should deliver 1 pint of gas or more into a catch container with a 30-ssecond run at idle.

Summit Racing has brand new Carter fuel pumps (not rebuilt) for Stovebolt engines for about $30.00 that will solve your fuel supply problems for good. "The ABC's of carburetion- - - -Always Buy Carter!"
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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