I've looked through the forums and there seems to be a lot on pressure washers but I have not been able to find anything quite like my problem.

I have a craftsman 2100 psi, 2 GPM, 5HP, 580.767100 pressure washer. I bought it used and it did not run. No idea how long it had been sitting. Cleaned the carb and got it working. The wand is a high/low wand, while in the high setting, several times when I would pull the trigger, and water would flow but there would be a second or two delay till the pump really kicked in and I got high pressure.

I was using it the other day and it did this, no big deal. But then when I stopped spraying for a second and tried to restart I only get a low pressure stream, the engine never sounds like it's doing any real work, and the pump never produced any real pressure.

I've check all the hoses, screen, etc, there is nothing blocking anything that I can find and there is no clear reason why things are not working.

I did noticed that there seems to be some air getting in. If I have the pump off and just run water through it there is a good amount of air that gets flushed out. once the water is running solid, no air bubbles, I fire up the engine. In the low pressure setting things seems to work just fine. I get the standard flow and pressure that I've always got. When I switch to high pressure I just get a smaller stream of water but it also sounds like I'm getting air pushed through.

I know nothing about pumps but I am comfortable tearing into stuff, I just didn't want to open up the pump with out posting for some help first. I'd hate to take something apart that wasn't ment to be taken apart and can't be put back together without some special tool/part.