I have a jet pump and it works good. Every once in a while the supply line will come off the pump and when this happens the pump itself is hot, I can re connect and put a little water in the primer and she picks it up and is good for a while. When the supply line come off from the suction side the water will come out off the pump so she appears to be full but she will not turn off and the pump is hot

Every once in a while the supply line will come off the pump

How on earth is that happening?

Not sure what your question is.