Small Engine Troubleshooting Problems? Ask a Mechanic Now.
Welcome to JUST ANSWER small engines, let me try to help you !! I don't know it all, but maybe together we can get you a satisfactory answer!
Make and model? When was it last used? Pressure washer? If it has water running thorough it, and motor is running, but no pressure when trigger is pulled, the unloader valve/spill valve is stuck, and needs to be removed and cleaned.
Washer is equipped with a ground fault plug. Does it reset? Does it have voltage to it? Do you have voltage past the fault plug? The trigger gun has to turn on the pump motor. So if no voltage past the fault plug, washer will no turn on.