I AM HELPING MY GRANDSON WITH HIS 72 PLYMOUTH SKAMP /6 AND WE HAD THE GAS TANK BOILED OUT AND REPAIRED FROM LEAKING. BLOWED OUT ALL GAS LINES WITH AIR. WE REPLACED THE MECHANICAL FUEL PUMP BUT STILL CANT FUEL UP TO THE CARB. COULD THE CAM LOBE BE WORN DOWN SO THE PUMP DOESNT WORK? LOOKING AT BUYING AN ELECTRIC PUMP AND JUST BLOCK OFF THE MECHANICAL ONE. ANY SUGGESTIONS.

Pull the mechanical pump out and "bench test" it, it could be a "bad" new pump with a stuck valve or folded diapham.
When the pump is out you can also look closely at the arm and cam lobe to see if that is making contact or worn.

Also check all rubber hoses for any leaks, a small leak on the suction side will pull-in enough air to keep the fuel from pumping. See if you can suck fuel up the line to the pump, the filter in the tank could be plugged.
You can always use a small can of gas and a short hose to the pump's inlet just to test the pump and front part of the system.
DD

THANKS DOC I WILL TRY YOUR SUGGESTIONS BEFORE GOING TO ELECTRIC FUEL PUMP. WE PUT A NEW FILTER INSIDE THE TANK.

sometimes a new pump will vapor lock..try pouring gas down the line from the carb,output side of pump...then cranking...it should start to pump if the diaphram is in good shape...this is a common malady for a pump thats been sitting on a shelf for a while.......best wishes.

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