Hi,

just bought(today @ lunch) a used pressure washer from a coworker. 5HP 2000 PSI.. I don't have all the specifics with me because the manual is in the truck. It had a carb rebuild last year.

He told me that it works great while spraying, but as soon as you release the handle on the wand, the engine will cut off. Also, to start the engine, you have to squeeze the handle or else it won't start.

Any ideas on what this might be? He said it just started happening.

Thanks,
robert.

The bypass on the pump is not operating. Since you say it is a 2000psi pressure washer, the chances are that it's using one of the cheap pumps. If this is the case, it would be better for you to try and find a used pump at an equipment junkyard or your local small engine shop.

Sounds like the in-line bypass valve has too stiff of a spring.
The bypass valve should be around 3" long and about 1" in diameter. it probably is brass. It's usually tees off from the output of the pump where the hose is connected. It contains a spring and a seat.
The spring usually weakens after a while which creates a condition where the pump always bypasses (when the resistance of the nozzle exceeds the by-pass spring pressure, the water takes the least path of resistance which is through the bypass and back into the input of the pump, this keeps the pump from deadheading), this restricts the high pressures from working properly. someone might have added washers behind the spring to stiffen it. This will make the bypass more resistant than the nozzle. That's why you have to squeeze the nozzle in order to turn the motor over when cranking. This is also why it dies when you let off the nozzle (the pump deadheads).
I suggest taking the brass bypass apart and inspecting it for shims, washers, or anything that could have been added. If nothing appears abnormal, then order a new bypass, someone could have added the wrong spring. DO NOT TAKE APART THE PUMP. I doubt anything is wrong with the pump unless you take it apart.
tav

Had the same problem with a generac g24 pressure washer with a Honda GCV160 engine. I corrected the problem though, it ended up being a exhaust valve sticking, carb cleaner, drill, and high temp silicon and it does just perfect. get to the valve stem hit it with some carb cleaner and or wd40 work the valve by hand if possible then remove the spring attach a drill to the valve stem if possible and run it slow very slow moving it back and forth while spraying cleaner on the stem every so often this should free up your valve issue if that is what it is. Then re-assemble I like High-Temp silicon(RED) and try it out. Hope this helps

What you describe sounds like either sticking check valves or your unloader valve is bad. Not knowing what pump you have its hard to point you in the right direction. Sears uses lower end pumps to keep the cost down to the consumer but in long run it can cost more. If you can get us the model # of the pressure washer and then we can get an idea of what pump it is and the right direction to point you in.