Thanks everyone for all the advice! This project took a while for me to suss out but I now have my Karcher 2400 from Costco working now - amazing! I initially wasn't going to do the repair 'cos I'm not mechanically minded but - hey, I did it. Yes, even me!

A few things I did wrong - when you first remove the 2 screws and white plastic top bit, underneath there is a spring and metal piece, Well this is NOT the spill valve, that's the next bit that you have to pull out with needle nose pliers, this would not pop out even with the engine running and all hoses attached (a friend got it out for me as it was very stuck).
We couldn't get it out at first and so opened the main unit by taking the 4 bolts off but you can't access it from there and the oil will spill out if you do this - not recommended. Just have to pull very hard.
When we put it all back together water was squirting out from the top white plastic bit (remember I'm not really into this stuff;) I started it up anyway and Yay it worked great and the leak stopped too.
Hopefully it will keep going.
On the side Costco gets full credit back form Karcher for returned units (even ones bought years ago). And will take them back, If you don't have the receipt they can look it up. An employee had one of these faulty units and told me his tales of woe and so knew Costco's policy. (i couldn't take mine back as a friend bought it for me).
Thanks again everyone!

Thank you for the complete instructions. I was able to repair my K2400 Karcher with Honda motor easily. The unloader vas dry, and with a wipe of the rag to be sure there were no deposits, and a lubing for the piston, it works perfectly. As a tip to folks who visit here in the future, use the plumbers grease. I picked up a small container for less than $3.00, which should last forever.

First of all thank you to everyone who has contributed to this forum. I had the same problem with my Karcher K2400HH pressure washer and wish I had found this site before I tried fixing my unit. What probably would have taken less than half an hour became a six hour ordeal. All part number references are from http://www.pressureparts.com/k2400HH.aspx

Things I did wrong:
- I didnt know that the unloader (Page 3 #12 spill valve) existed and assumed I had to take the cylinder head (Page 3 #15) off in order to get to the pumpÂs components. I also didnÂt expect a bunch of oil to come gushing out when I pulled off #15 (which was also connected to the piston guidance Page 3 #4). One poster had asked about the color of the oil. Mine was grayish (probably due to metal mixing with the oil) with a hint of light brown. I figure my unit had run for about 100 hours before the failure.
- When I put the cylinder head and piston guidance back on I put the pressure washer on its back (pull cord was on the floor) so that I could put oil back into the pump (Karcher says to use 100 ml (3.38 ounces) of 15W40; a small engine repair shop recommended 30 weight non-detergent pump oil). That was a major mistake. Engine oil from the GC160 Honda engine ended up in the air filter, carb, and muffler. Needless to say it took some time to clean these out. I should have removed the pump from the engine housing at the four bolts (Page 4 #9), filled the pump with oil, and then bolted it back onto the engine.

A few things I found:
- If you have already taken the pump apart (piston guidance separated from cylinder head) you can access the unloader if you remove the joining piece (Page 1 #12). My unloader was stuck, and I was able to use a very small flathead screwdriver and push its spring up to force the unloader out of its hole (after removing all the components listed as #9 on Page 3).
- Someone had asked about where to find o-rings. I did a search on Ebay and there are places where you can get o-ring kits (30 different sizes, about 400 total o-rings) for around $20. I donÂt know what quality they are or if they are the correct sizes but if I have to replace the pump, hose, and wand o-rings IÂd be tempted to try these out. Worst case youÂd have an o-ring kit for your homeÂs faucets if none of them worked for the pressure washer.

One last note:
- When I lubed up the unloader the first time the washer would pulsate between high and low pressure (about three seconds high and then three seconds low). I removed the unloader and not only put additional white lithium grease on the o-rings but also tightened the unloader (while compressing its spring) clockwise by about one turn. It seems that the washer now eases slowly into high pressure mode where before I recall it had a harsher recoil after pressing the trigger.

Again thanks everyone on this forum for helping me get my washer back up and running. I hope somebody is able to benefit from the mistakes I made.

I have a K395m plus pressur washer and replacing broken plastic Karcher Water Inlet Elbow. took off top piece but can't figure out how to take the water inlet elbow off. Is there any link that shows how to do this without breaking something else?

So I have now found out that Karcher has the was tech support of any company I've had to deal with. My problem is I have a G 3000 BH that will hold high pressure for about 5 seconds and then go to low for about 2 seconds. (keeps doing this over and over) I have cleaned and greased the unloader valve but it didn't seem to work. Karchers part list shows the spring and then what looks like a o ring or something and then the unloader valve. (spill valve) Does anybody know what that is? Any more thoughts?

I'll also started taking the front off of the pump and some oil came out. (not all) What is the best way to put the oil back in? Above it said if I tip it back oil in the motor will get into the air filter, carb, and muffler. Any thoughts?

If memory serves me correctly there is an o-ring, copper thingee, and spring that sits on top of the unloader (spill valve).

This is my guess for the purpose of the copper thingee:
As the water is looping through the pump (engine turned on but trigger on wand not being pressed) it warms up and could potentially get too hot and damage the pump. I think the copper thingee will expand, thus not allowing it to be pushed against the o-ring. This should allow the hot water to be expelled through the white plastic piece (the first thing to come off after you removed the two torx screws).

If you have to remove the pump from the engine I think you will need to do it closest to the engine block. That is where I plan to remove it next time. I dont believe that any oil will leak if removed from that location. Once you have the complete pump separated from the engine block, then you should be able to remove the four hex bolts closest to the water inlet and refill your pump with oil. I found putting the pump back together is a lot easier if you have an assistant.

As for the pressure washer cycling from low pressure to high pressure there are two things I have read which might cause this:
- The flow rate of your garden hose may not be high enough. You might also check the pumps water inlet filter and make sure it is not clogged. You might also try removing any backflow preventers on your garden hose if they are present.
- If one of the valves on the high pressure side of the pump is stuck open (I think those valves are underneath the rectangular metal plate [1 inch by 3 inches] it might also cause this.

If you get your washer back up and running Id like to hear what you did to fix it.

Good Luck,
Steve

Hey Steve just got done working on it. When you take the 2 screws out all that comes off is the white piece, (that the screws go through) then up inside of that is a o ring, then a bullet looking brass piece, and then a spring. After that is all removed then is the unloader/spill valve. You said you think there should be a copper like o ring in between the spring and unloader/spill valve correct? It looks like there should be something there according to Karchers parts picture but they told me they weren't sure.
How hard is it to remove those other pressure valves? Is there oil or anything behind them?
How I got the oil back into the pump is by draining the motor oil so I could tip the pressure washer back somewhat and not have oil getting into the carb and air filter. Need a oil change anyways so that part worked great.
Thanks for the info and anymore would be great. This forum has been a great one for info.
One last question, could it be something to do with the wand and pressure hose?

I took a look at the parts diagram, and if memory serves me correctly there are two rubber o-rings on the white piece (the one that the screws go through). One is fairly small diameter and is buried up inside the white piece (this one makes contact with that copper / brass bullet shaped piece). I think the other o-ring is also connected to the white piece (where the white piece mates to the pump). For sure I didn't have any copper o-rings in mine.

I'm glad that you were able to get the pump filled back up with oil without having the remove the pump from the engine block. I'll have to remember next time to drain my engine block before tipping the pressure washer back.

I did try to remove that metal rectangular plate (with hammer and chisel) and got it to slide about 1/2 inch before I decided to try something else first. There should not be any oil in that section of the pump. My biggest concern about removing the metal rectangular plate was that if it had to come completely off those L-shaped hooks that it might be really hard to get it back on. I was also concerned that the spring loaded high pressure valves would come shooting out from those three holes once the metal rectangular plate was removed. Looking at the diagram there appears to be a plug holding the high pressure valves in place after the metal rectangular plate is removed . . . but don't take my word for it since I'm just looking at the picture. It is possible that crud / mineral deposits is causing one of those valves to stick in the open position. If you end up working on this section I'm curious what you find.

When you cleaned the unloader did you also use a tooth brush / wire brush to clean out the hole that the unloader came out of? And what was the condition of the rubber o-ring on the unloader (scuffed up versus new looking)?

I remember reading that it is possible for the nozzle tips to wear out (can't remember what the symptom is though). Have you tried different nozzle tips? And have you checked the o-rings on the pressure hose and wand?

Also do you get the same high / low pressure cycling if you run the engine at 1/2 to 2/3 throttle? If you don't you might try a web search for this and see if you can find anything. I can't remember what the possible causes of this behavior are.

Good Luck,
Steve

Hey Steve I tried a new wand and nozzle and it worked great. I then put my old wand and nozzles back on and it started happening again. Looks like after all that work it was the simple stuff. At least everything has new oil and is cleaned and greased. Thanks for your help.

I have a Karcher 396M. Upon turning switch to on, motor surges on and off continually, but when trigger is depressed motor will run full time while dispensing water under pressure. Let off the trigger and motor returns to surge mode. Why the surge and how do I fix it?

I have a lightly used K2400hh,several years old, which has lost hi pressure. Perviously this was fixed with a new unloader valve. Not this time, also tried all the suggestions listed above, to no avail. Pump bearing don't make any noise & Honda engine runs fine. Any additional suggestions on what may be the problem?

I've always found karcher washers to be good quality, mines lasted years. I don't use it every day but it does take some abuse! Tool Guru have a good selection...

Is the o-ring in the plastic unloader cover in decent shape?

Yes it is.

My Karcher Model HD 2700 shuts down after 15 min operation. After 5 or 10 min I can start it up again but the cycle gets repeated. It has the Honda GX 200 engine.
I assume the engine quits due to 'overheating'.
The oil level is NOT low so I don't know what else might cause this interrupt operation.
I am a 'do-it-yourself' kind of guy and have no problem trying to correct the problem myself...if I knew the reason for 'overheating'.

Is the pressure nozzel bloced. This can prevent pressure from forming

Here is a GREAT service manual..

http://www.scribd.com/doc/35848425/Karcher-5-Hp-Horizontal-Pump-Service-Manual

Apologies to all. I found the correct one.

http://www.karcherresidential.com/support/downloads/pdfs/handbooks/pumps/Pump_629.pdf

Add one more success for the "tommyw" tip. After thinking I had a crack in one of the washers and changing them all out this tip fixed the problem perfectly.

Thank you for taking the time to post the tip!!!

Bill

Anyone have an answer to Mike's question posted by esoxlucius (My Page) on Sat, May 8, 10 at 12:48 on the high pressure hose connector leak? My hose connector, although tight, also flops loosely and leaks which affects pressure. Is there a seal replacement fix?

I have a Karcher pressure washer and found helpful / interesting reading all the forum notes. My problem - where is the uploader value on the KArcher model 3025? I am ready to attempt the repair of the value as suggested by so many folks, but I don't see the black removeable piece on my machine. Someone please tell me where to get started on the project by locating the value. Thanks.

For anyone interested here is a link for the Service Handbook for the 3.532-629.0 washer pump used on the K2400HH model.

I have a K2.26 M and i cannot get any pressure out of it..I just have it for almost a mont..i tried the mixing option once with some bleach - detergent...
it started leaking two days ago heavy and loosing pressure...today he had no pressure at all...
can anyone help me? Thank you ,Gilbert..

Help Please! Have a used Karcher 395 electric pressure washer. Prior owner said he only used it twice. It does look new. Tried it and have no pressure, just light stream of water which shoots about 6 feet. There doesn't appear to be anywhere on the machine or the wands to regulate pressure. Am I just doing something wrong. Also why does it have two trigger guns. Thanks for any suggestions.

On my 2500 VH, I too pulled the pump and am in need of servicing it after reinstallation. I have read two threads, one stating to unbolt the pump from the motor and add oil that way. The other is to drain all the oil out of the motor and turn the unit upside down and service the pump. Which is best or is there another way? It seems to me that even if the motor oil is drained, a small amount will very likely still leak into places it shouldn't. Any advice?

all you guys who had water spraying out top of unloader cap and some pressure and motor bogging down when let go of trigger, same thing happened to me :)

i put back together in correct order and all works great.

unloader valve goes in housing, then spring goes on top of unloader valve, then brass valve thingy then cap.

cheers,
pete

The basic $98.00 unit with no wheels don't know mod no.
When 1st used new out of box, it took several minutes for the pump to kick in. I thought it was maybe usual for a new unit to prime pump ?? or similar.
But after a few months in the Garage it won't start at all.
I only get tap water preshure thru the unit.
Lost reciept. Hardware shop just say sorry. Might have to try a Gerni unless someone can advise me.

I have a model K3.86M 1.636-121 Karcher pressure washer, Serial Number S 341586 1/05 that has a water leak and I took out all the screws but cannot and don't know how to take off the blank part that has the handle on to remove it to see where my water leak is. What is the trick to remove that handle part?

I have a 2-3 yearold pressure washer that has been used only once. The problem that I have is that there is nno pressure. Please explain what it could be. thanks

i have replaced the fuel hoses to my washer hds501c now it does not seem to be getting fuel do i have to bleed the system as burner will not start

I have a karcher mod# K3.47M. I always put the washer in the garage after use. We had some very cold temps this past winter and the discharge elbow cracked. I went on line and bought a new elbow #9.036.7030 and it would not fit. The serial # is 027270. Can anyone tell me what # elbow i need and where to get it. Help,Bill

I did the grease thing (had to start the washer, with water on -- a geyser poped out the piston). Still did not work ... I adjusted the engine RPM down (phillips head screwdriver to adjust the RPM) & now it works great. I'm sure the grease was the issue, I monkeyed around with the carb yesterday & just left it at high RPM. Clearly a pressure-feedback piston .. engr should have made it out of teflon ...

Wish I saw this before I attempted to repair my 2400.
Finally found the spill valve nothing was gettin it out pliers worked it back and forth pb blaster, brake clean etc. FInally took out the 4 bolts so I could get needle nose vise grips on it. Worked back and forth for 20 minutes. Finally poped out. Cleaned valve and housing with 3 m pad greased and reassembed twice Now I have to idle to get pressure and hold trigger and increase RPM to maintain pressure. Hlep! should I grease it again?

Re: K 2.360 - Piece of junk . Brand new . Bought from Wallmart Today . Motor will not start . I have 65lbs of static water pressure . 120volts AC . Tested the GFCI and it passed . Pressed reset again . Switch is in the ON position . Trigger is pulled . NO MOTOR FUNCTION . Can anyone help , or do I take it back ?

I have white oil below pump housing. what type oil do you replace with and is it supposed to be at the clear window level on the side of pump. I have Karcher HD 3101

I have an Karcher 395 pressure washer that doen't turn off when I release the trigger. After reading, I can assume it has something to deal with the spill valve or pressure control valve (see http://www.fixya.com/support/t5329991-motor_not_shut_off_when_trigger_wand).
Can someone assist me on exactly how to service it?
I already removed the cover including the electrical box which I figured the switch that has 4 leads to it is the switch that shuts off motor as pressure builds when triiger is not engaged, as there is a plastic piece that ends outside of box trough a rubber gromet that should react act this occurs. Assuming I understand the design, I figured the valve is the part with 1 screw attaching it, which has a metal rod.
Is this what I unscrew and if it doesn't come out by itself )which it does not), turn motor on/off quickly to make it pop out?
Please advise if I am correct along any additional info you think will be useful.
Thanks in advance.
RJ

hi there, to all you frustrated pressure washer users, its self evident that this is a demic product with all the problems attached to them, I'm going back to the good old reliable bucket and water, lifes too short.

I have used my Karcher pressure washer very little, however, I have a problem, after it runs for about 15 minutes it shuts down. I have stopped it and as soon as I use the spray handle, it stalls and goes out.. I got about 1/3 of my deck done, so now I am borrowing the electric pressure was I gave to my daughter. Any suggestions?

I have K390 karcher pressure washer when I try to turn the machine on machine on it will not start it was working but but that was only accasionaly before is there a electronic switch behind tha botton if so where can I get one and what is the part number
thanks Jack

I've got a 6-year-old Karcher 2400 which I just brought back from the dead following the instructions on this site. I'll sum up, and add a photo:

1. Rebuild the unloader valve following the instructions on this site. See photo for location of valve.
2. Be sure to attach the sprayer hose and turn water on full blast before starting up motor--I couldn't dislodge the piston until I did this, and the fix didn't work until I did.

Upon performing these steps to the letter, I brought back an old Karcher that I thought would never work correctly again. Good luck.

I have followed all of the advice regarding low water pressure on a Karcher 2400HH machine. I have replaced the "spill valve' with a new one and lubricated it with Silicone plumbers lubricant. The pressure is much better but it occasionally dies and then resumes at full pressure. Is there something that I missed or is an additional step necessary?

I have a K3.99 pressure washer. I use it about 4 times a year, and I think it is only about 3 years old. I had used it the week before and everything was fine. I went to turn it on this past weekend, and the power is completely dead. Is there a fuse inside that I need to replace?

I registered for this forum simply to say THANK YOU to those who offered advice about the unloader valve on the 2400HH. It had never worked properly from the day I bought it (new) several years ago, but I [wrongly] attributed it to bad water pressure from the tap and was just pleased when on occasion it would "spring to life" and provide real pressure (perhaps one time out of ten). The problem continued even after moving to a new house, by which time I was well out of any warranty and I just resigned myself to living with it, figuring I had gotten a lemon and was stuck with its quirks (unless I wanted to pay a repair shop a ton of money to sort it out).

I stumbled across this thread looking for something else today and immediately went out to follow the advice offered here. Wish I had done this years ago -- it works MUCH better now than the day I took it out of the box! Thank you so much! Can't wait to see my water bill for the month, as I've been going around for the past several hours looking for anything that looked like it could use a good power washing. :-)

I have a Karcher 330 (electric) used very little - problem is.. no pressure.. any suggestions..

Hi all, am new here after Googling problems on Karcher 2400 HH purchased at Costco about 5 years ago. Having the same pressure problems as many. I have broken the attachment fitting off the end of my trigger gun and am awaiting the arrival of a new one that I ordered from PressureParts.com. They informed me of this unloader problem. So I get to it and can't get it out either. Couldn't get any tool in with that cross member in the way. Naturally I hadn't got here yet before loosening the pump front and spilling oil. Doh!So pulled the whole thing off from engine and struggled but got the spill valve out with needle nose vice grips. Not really caked up at all but O rings were brittle and beat up looking. So I'll get some new o rings and get it it greased up while waiting for the new trigger gun. As well as getting some of this unobtainium oil and either topping up or replacing. Like others have mentioned it doesn't look as good as one would hope it might. Apparently a lot of these guns broke like mine (where the tube is soldered to the threaded fitting) and they have redesigned the plastic housing to better support that joint. Hope to have some good news in a week or so and share any thoughts and experience as many of you have done. Thanks to all!

Oh and wanted to mention a couple of things:
1)Most hardware and auto parts stores have vast collections of o rings you can buy individually. Take in your old ones to compare and/or have them measure with a caliper or micrometer.If no luck there try McMaster-Carr online. They are wonderful for all kinds of things.
2)If you live where it freezes like I do in CO and if you have or can borrow an air compressor and an air nozzle you can blow the water out of your pump and hoses. I have done this successfully for at least 6 years that I've owned it and I store it in a shed that gets well below zero at times.
Hope this is helpful!

I lubed my Karcher's unloader with plumber's grease last year and it worked for a while. Took it apart and found the sides of the piston and cylinder were free of grease and dry. Going to use lithium grease as suggested.
About winterizing. I buy RV antifreeze that WON'T HARM THE ENVIRONMENT! Suck it out of the bottle with a piece of hose attached to your inlet and spray it out of the wand until everything is flushed and filled with the antifreeze. Just hook up everything normally next season and spray it out on the ground, over the lawn, whatever. It won't hurt anything and once you're spraying clear water get to work.

Have been having unloader problems for years on my karcher 4000 PW. Finally learned the water pressure trick to eject the unloader and now keep it liberally greased. Last time i reassembled the valve I wound up with low water pressure and started disassembling, then cleaning the entire pump head with no improvement. Obtained an exploded view diagram of the pump and found I had the brass bushing atop the unloader backwards. Flipped it around and had great high pressure!

I have a small Karcher powerwasher with a Briggs engine. I had no pressure at all. On my model, the unloader value is in a very difficult to reach area behind the front sheet metal panel. I was able to remove the two torx screws, but the valve would not come out when restarting with the water on.

So, I was forced to remove the four bolts holding the pump together. A bit of oil (4oz to be exact) came out, but at least I could better examine the unloader valve.
I had to use a needle nose vice grip to grab on to the valve and yank it out. It did not come out easily. I lubed it up liberally with white lithium grease and reassembled the unloader valve.

The specs for the pump oil calls for 4 oz of 15W40. All I had was a quart of Amsoil 10W40 synthetic that I use on my Harley. They say if you don't have 15W to use 30W.
I can't see that this would make a big diff on a washer that is already on it's last leg, so I filled it with 4oz of the Amsoil and topped off the engine oil with the same. Purrs like a kitten and the unloader works like brand new.