Found the answer in the truck shop manual. The dual action fuel pump cannot be cycled by hand due the the heavy pressure supplied by the spring in the vacuum side of the pump.


"Pay attention to the details! It ALWAYS pays off."

1949 Chevrolet 3100 Series 1/2 ton Pickup
1964 Chevrolet C10 (Ol' Yella) (SOLD)
1958 Chevrolet Biscayne 2 door (SOLD)
1970 VW Beetle