I have a 90' drilled well with a 2 line jet pump. My pump was cutting in and out every couple of minutes. I watched and it would cut out at 52 PSI...I thought that was good. After it would cut out, I watched the pressure gauge and the needle would immediately quiver downward and the pump would cut in at 40 some PSI. I did not know why there was a sudden drop in pressure, but I thought the pump was turning on pre-maturely and assumed a bad pressure switch. My water worked fine in the house at this point.. ...I turned off the power to the pump. There is a tire valve stem (similar to the one on the pressure tank that is mounted next to the ouput line on the pump. I pulled off the rubber boot on this and it started dripping. I depressed the needle valve temporarily to try to get it to seat. It let out a small amount of water/air so I capped it with a tire valve stem cap to temporarily stop any leakage. I then turned the power back to the pump. It came on as expected. However, it stayed on and would not build pressure. Stayed at 40 some PSI. I check my house water and had none. I assumed I lost my prime. I disconnected the pump outlet line that feeds the pressure tank and gravity fed water to fill the pump casing and top off the inlet lines. (only other way to prime was into plug, but that was side mounted and did not work well) I thought a gallon would do it, but ended up pouring 15+ gallons in before it started to appear full. I tried to run the pump and expected the prime to take and have water pumping everywhere. It did nothing. In fact it would then take more water. Do I have a bad foot valve? or leak in inlet line? Help!