The gfi is there for a reason and for safety's sake should not be messed with. I'm not an electrician and am not clear on how it works but there is obviously a problem with the machine's wiring. How old is it, can you exchange it under warranty?

Just as a follow-up. An electrician friend suggested the following.. cut off the GFI plug, cap the ends of the wire securly and plug it into a live socket. If the breaker trips with no passage of electricity,(the wires are capped) then the gfi is bad. If the gfi doesnt trip, then there is a voltage leak in the sprayer itself. Either repair or replace. As it is, the breaker pops, so the gfi itself is bad. I'll pick up a new gfi plug and fix it.

If the GFCI plug on your power washer is bad, your power washer's electric motor won't start. If you know that the outlet you're plugged into has power (plug something else into to it to be sure it does) and your extension cord is good (try switching it out) then there's a good chance your GFCI plug is bad. If you try to reset it and the GFCI plug won't stay reset, then it surely is bad. Having been left out in the rain is another clue that might be the problem. In any case, to buy a replacement plug from the manufacturer might cost you $45. The answer: For $18 buy a Leviton 15 AMP GFCI outdoor plug and it will work perfectly. Just remove your old plug and take it with you to see that you're getting the same type of plug--should be easy to find at a big box store, such as Home Depot. Put it on and you're back in business.