Purney,

The fuel pump can be difficult to install. The actuator arm must be partially compressed against the cam lobe in order to bolt it up to the block. If the actuator arm was severely worn or the cam lobe was devastated, the pump wouldn't move sufficiently to tranfer fuel. This is possible, but not very probable. What is more likely is that the line is plugged somewhere on the suction side of the pump.

It could be inside the tank, or maybe a collapsed hose in the line somewhere. A plugged suction line would be much more probable considering your pump worked manually, but not when attached to the supply line from the tank.

Stuart