Question about Karcher 2500 PSI Pressure Washer

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Very low pressure after a few seconds

I have been told that it might be the unloader valve but i am not sure how to clean the valve and maybe replace o-rings

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  • mickeywalker May 14, 2010

    thank you Kelly I Got both pumps working great without tearing them apart your tip worked great thanks again. I will be sure to add winterizing fluid from now on.



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These pumps are notorious for seasonal problems.
Tip the unit to the point you can pour engine oil into the water inlet connection. What your attempting to do is free up the ball seats in the pump. They get corroded when they sit and lock in place. Adding the oil or a vast amount of WD 40 to the water inlet often does the trick for loosening up the seat balls and springs.
After you add the oil (3 - 4 ounces) or WD 40 to the water inlet line just slowly pull the engine through with the ignition switch off. As the water inlet cavitates add more oil.
Let it sit over night and then take a block of wood and a hammer and tap on the power head. Don't over do it and do it in such a manner your not going to shear off any bolts or break anything. But... be serious with the hammer and block of wood.
Then connect inlet water hose, the pressure hose and test the unit. You may want to purge the oil lubricant into a bucket before you start the engine.
Give it a try and see what happens. This works more often than you would think.

Thanks for using FixYa,

Posted on May 04, 2010

Testimonial: "thanks I will try that it makes since because when I start it up I hold the trigger to relieve the pressure and have good pressure until I let go and the next I pull the trigger nothing but regular house pressure"

  • Kelly
    Kelly May 13, 2010

    One more note: If you again have to get into the unloader valve, lubricate generously everything with No. 105 Lubriplate "white" grease. (Plastic tube available at auto parts stores)




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