Karcher 2500 pressure washer pulsating?

pressure washer unloader image

Jamie

I have been working on a karcher 2500 pressure washer I got in a garage sale. I have taken down the pump and replaced some of the valves and the spill valve. The hose it came with was cracked, but I didn't get a new one until I thought I could get every thing working. Once the pump was put back on it ran fine with the cracked up, but the pressure was lower than I thought it should be. I figured it must be the hose causing my pressure problems, so I got a new one. Ever since I put the new hose on the pressure wash pulsates (It has full pressure for a second or two then it loses pressure for a second or two.) Any ideas what could be causing this?

Answer
This should be an easy fix. The unloader valve is sticking....quite a common problem for Karcher machines. On the top of the pump you will find a black plastic cover with a chrome button on top of it. Pry the button off and lift the black plastic cap off. You'll find two star or hex screw under it....remove these and carefully lift the plastic retainer up. You are now looking at the unloader valve assembly. You'll need needle nose pliers to to remove it. Look down into it and you will see a tab to clamp the pliers onto. Gently twist it pulling up slightly at the same time. Once you have it out, clean it and apply some silicone grease to it and replace it. Put everything back together the way you took it apart and your done.

How to tell if 1600 psi electric pressure washer pump is toast?

Big Yoda

the motor comes on but not the pump. Does the pump give off its own sound? the water pressure is not being boosted.

Answer
assuming you have adequate water flow to the machine

check if the water inlet filter is clogged
check if the unloader valve is stuck
if you don't know what that is
google search unloader valve+theBrand off your machine
if all thats ok you probally need to rebuild the pump

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