How to Fix a Pressure Washer (Part 1 of 2)

Watch how to diagnose low pressure issues in a pressure washer as Mark disassembles the washer's pump to find the problem.

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[Spz]

I am in debt to you guys. :) Thanks a ton.
I received a Karcher 2800OH from a co worker. It was not building any pressure, regardless of how much pressure was on the intake hose.
With this guide, I Tore down, cleaned and rebuilt the pump, and it works like a champ now. :)

Thanks Guys!!

[wesleyhester]

Sir, thank you very much for your detailed video. I JUST serviced my karcher pump after losing pressure, using your video as a guide. In fact, I paused the video a lot during the disassembly and reassembly. My unit is a year newer than the one in your video, so my repair was simple. Luckily my issue was only light valve and brass casing corrosion, no parts other than a few o rings and grease was needed for tighter seals. Thanks again!

[FIXTechGuides]

@th19940305 Good question. Most pressure problems lead to the pump. If you've eliminated that the problem isn't located in the hose, gun, or nozzle, then you'll have to disassemble and clean the pump like in the video. If the cause is something more than just a dirty pump, then dismantling it and cleaning it should reveal what it is. As for what exactly might be causing the issue, it could be almost any part in the pump. Check each part for wear or damage and replace those that need replacing.

[FIXTechGuides]

@Spz03737 It is great to hear that you where able to fix your pressure washer yourself! I bet you saved a bunch of money doing it yourself and probably had a little fun in the process!

Thanks,

-Mark

[FIXTechGuides]

@linked2gether It is possible but it would require some research. The most obvious issue is the mounting. You will need to make sure that the engine shaft is compatible and you might need to fabricate a mounting plate to mate the pump and engine together. The other issue is if the engine has enough power to run the new pump. The manufacture of the pump usually works closely with the engine manufacture to source an engine that will meet the requirements of the pump.

I hope this helps,

-Mark

[CVKEJ]

This video is very helpful. I just happen to have the same exact pressure washer with little to know pressure. Do you happen to remember what parts were ordered for this pump? Is taking it apart the only way to change the oil in this pump? The pump is probably about 20 years old. Amazed that you chose the exact same machine for your demo. Thank you for your time.

[robertgraydon]

Thanks for this detailed video. I have the exact same problem on a used Karcher exactly like this one. I had already disassembled the pump, cleaned and reassembled but I did not discover that unloader spill valve piston until watching this video. I am confident I will get mine working tomorrow after addressing that valve. Everything else looked fine on mine. Thanks a Lot for the tips. 

[FIXTechGuides]

@mrFoos54 It does sounds like the piston seals. Probably the three closest to the engine. When I rebuild a pump if I find evidence of one set of seals being worn I will replace both sets. I figure if one set is causing a problem the other can't be far behind.

Thanks,

-Mark

[FIXTechGuides]

Most pressure washers require the engine to spin at a constant 3400 RPM's. If the engine RPM's are even a few hundred RPM's too fast or too slow the pump will not pressurize or the pressure will surge and die. I would check the RPM's first. If that tests out OK then you will need to open the pump to see what has failed.

I hope this helps,

-Mark

[dixiegriffinjr.]

some of the best DIY videos on you tube

[FIXTechGuides]

@tudinerito Hi, the pressure washer will not pull water from the river on its own. It requires a pressurized water source that can provide the pump's specified CFM requirement. Using water directly from the river will also ruin the pressure washer's pump very quickly. The pump requires clean water, any sand or sediment in the water will wear the pump's components very quickly. Many pro's even filter house water before it enters the pump. I hope this helps and thanks for watching.

-Mark

[BigDogsHunt]

suggestion: remove the unloader valve BEFORE taking the pump assembly off the unit.
1) hook up the hose and turn on the water.
2) remove the cap, 2 torx screws, and white plastic housing.
3) pull the starter cord.  The engine doesn't have to start, just needs to crank a few pressure waves to pop the valve out the top. :)

[BartHull]

I pulled the unloader valve, cleaned the corrosion in the aluminum casting and greased the o-rings. Works like a charm, no more low pressure and fooling with removing the tip. Thanks

[rickylain]

i have a new washer 2600psi that i only used a few times. when i first start the engine, i put it to choke. but when i run the engine lean, the engine dies every time. is it the engine or the water pump assembly causing it? thanks.

[josephphillips]

I need this guy to fix my pressure washer

[xXitachiXx]

what type of oil should i buy to replace the old oil?

[dennisseger]

Thanks for the video Mark. I took the pump apart, cleaned it, and replaced the unloaded valve I ordered from E Replacement Parts, great site by the way. I have a Karcher  G 2600 VH. As soon as I run water through the washer the engine stalls and shuts off. I have to use a wrench to loosen the hose off the handle because there is so much pressure built up. I did replace the unloader valve and only added lubricant to the top O ring and seated it. I am at a loss for what is causing it.

[tonyneedham]

I have a simpson pressure washer ps4033 with a AAA pump # 530004. After replacing the outlet valve, no pressure and the valves broke again. I then replaced the outlet valves a second time along with the unloader/bypass valve and a new boost valve bit (which appears some sort of relief valve). Still no pressure in fact, it is little more pressure than when the machine if off. What should I try next?

[michaelcarboneau]

Great did not indicate what type of oil to use upon reassembly. Can you please provide that information?
Also, is there a parts kit avalable for rebuild or do the parts have to be ordered separately?
Thank you for your help.

[BaSiLLiSKoS]

Hi and thank you for the video. 
I have a G3050OH (Karsher) with a Honda GC190 engine. Last year I cleaned up the carburetor on it because the idle speed was always fluctuating up and down. So I tore the carburetor apart and cleaned it thouroughly and the idle speed of the engine was finally ok..

I did this at the end of last year before storage and I didn't think about it but I ran the engine and pump without a water supply. I don't know if I damaged the pump.

This year I wanted to clean my car. Took out the pressure washer, it had fresh gas in it with stabilizer (and no ethanol), plugged the water hose to it and it started perfectly. 

I then pulled on the trigger and nothing happen other than the engine loosing a couple of rpm. No water pressure at the end of the hose. Looks like the trigger doesn't raise the RPM of the engine. But if I move the governor and raise the engine revolution, there is pressure in the water.

DID I KILLED THE UNLOADER VALVE last year by running it dry?

What should I do?

Thanks for the awsome video by the way, will use it as futur reference.