I have a 60' 2" well with a jet pump. It had a 1/2 HP motor. Recently the pump lost it's prime and I was unable to re -prime. Pulled the 1" pipe out and replaced the foot valve and the two leather seals at the jet. It now builds pressure to 60 PSI and holds it there. The new problem is when you turn on the spigot the pump kicks on at 40 PSI and the pump steadily looses pressure. I changed the motor to a 3/4 HP with no change in results. All testing was performed with the pipes isolated to the pump area by the house shutoff valve to eliminate leakage in supply line. Pressure tank is good. What else could be causing the drop in pressure?