We have a red antique deep well jet pump with 2 intake holes and no real identifying characteristics other than it has a GE 3500rpm 3/4hp motor on it. How can I find out if the pump itself is bad or if is something in the well. Initially we tried to reprime the pump. The pump took little over a cup of water and would not come up to pressure (25psi max). When it gets to about 25psi I crack the valve to open a little and the pressure goes to zero and the motor shuts off. I took this to mean that the water was getting to the pump and the pump is not pumping the water through the rest of the system. Is this a correct assumption? If so and the pump is bad, should I replace the innards of the well casing along with the pump?