Is your machine a hydramaster raptor if so nobody could fix mine hydramaster put a new pump head on but that still didn't work the only way I could the pump to go above 200psi was to put the preasure gauge to 300psi then press the trigger on the wand at the same time keep turning the preheat on and of and after about 10 seconds it will jump to about 200-250psi had to do that evey time ended up getting rid of it and bought a powerflight.I think its something to do with the pre heat gauge.