[601HP]

Yours are running as designed. Once line pressure is reached, the pump pulses very slowly. When I test one of my rebuilt pumps, its connected to a flow valve and pressure gauge. With the valve wide open, the pump races. As I dial back the flow by closing down the valve which simulates increased line pressure, the pump slows waayy down! It may pulse once every 0.5 to 1 second.

I'd dial the pressure back to between 5 and 6 psi.

David