pressure washer issues

   / pressure washer issues #1  

rambler

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Jul 6, 2003
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MN
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Ford 960, 7700, TW20, 1720; IHC H, 300; Ollie S77
Got a cheaper Karcher washer several years ago. Gas powered, 2400psi.

So, for a while now, it doesn't like to pressure up. Squeeze the trigger, and a small stream of water spits out - just passing through.

If I take the tip off, pull the trigger, a full stream of water passes through, appears to be 'pressurized' but of course with no tip it's just passing through. When I release the trigger, it appears to 'power down' a bit more.

Put the tip back on, and then it will work fine when I pull the trigger, good pressure, nice fan tip spray, works well.

Let go of the trigger and it stops spraying, but won't start sprying again the next time - just dribbles a little water out the nozzle.

Repeat.

Something isn't right?

--->Paul
 
   / pressure washer issues #2  
Sounds like the pump is shot.
 
   / pressure washer issues #3  
I had a cheap electric one that did the same thing. I think there must be a pressure reduction sensor in it somewhere that either turns on the motor or in case of gas powered, kick up the throttle when the trigger is pulled but I didnt find anything when I took it apart so I just trashed it and bought a gas powered one. So far the only problems with it has been carb and trigger on the gun. Had to get a new gun as when it pressured up the plastic trigger would bend before pushing the valve plunger. I used it a while by just tying the trigger open but that is dangerous at best.
I dont think the pump is shot if it works when you remove the tip. Look for that sensor and replace it if it is not built into the pump.
 
   / pressure washer issues #4  
The unloader valve is sticking and can be replaced easily. Just don't take the four bolts out of the bottom of the pump or you will dump out the oil. The oil for that pump is like $18 a quart.

Most of the Karcher pumps have a black cup that is held on by a push cap. Remove the cap, remove the two torx screws to remove the thermal relief valve. the unloader valve is under it and can be removed by grabbing it with a pair of pliers and twist and pull is out, reverse to reassemble.
 
   / pressure washer issues
  • Thread Starter
#5  
The unloader valve is sticking and can be replaced easily. Just don't take the four bolts out of the bottom of the pump or you will dump out the oil. The oil for that pump is like $18 a quart.

Most of the Karcher pumps have a black cup that is held on by a push cap. Remove the cap, remove the two torx screws to remove the thermal relief valve. the unloader valve is under it and can be removed by grabbing it with a pair of pliers and twist and pull is out, reverse to reassemble.

That sounds like the situation. It pressures up great, can strip wood into fibers yet just fine; but the unloader deal is fussy.

Now, to find where to get one. :)

Thanks.

Edit: Well with some words from your message, found this in a couple minutes, of search, looks like the first step, otherwise replace it & see parts listed online. I love steps 8 & 9. :) :) :) :)

As well on the bottom note, we have very hard/ magneese water 'here' so that's part of the issue.

--->Paul
 
   / pressure washer issues #6  
The unloader valve is sticking and can be replaced easily. Just don't take the four bolts out of the bottom of the pump or you will dump out the oil. The oil for that pump is like $18 a quart.

Most of the Karcher pumps have a black cup that is held on by a push cap. Remove the cap, remove the two torx screws to remove the thermal relief valve. the unloader valve is under it and can be removed by grabbing it with a pair of pliers and twist and pull is out, reverse to reassemble.

is this the similar to all gas pressure washers? should the unloader valve be maintained by regreasing it or cleaned to prevent sticking?
reason I ask is because I have a troybilt one that takes a little while to pressurize. sometimes I have to squeeze trigger quickly to make something unstuck or clear to make it work again.
 
   / pressure washer issues
  • Thread Starter
#7  
Just reading on the web, it appears the model I have is known for this issue, but probably applies to all of them somewhat?

I forgot to include the link in my messaqge above for my issue:

http://www.paddockdrayage.com/Karcher/index.htm

--->Paul
 
   / pressure washer issues #8  
My pressure washer may take five minutes or so before I have enough pressure to blast with, but I guess that is normal for it.
 
   / pressure washer issues #9  
My pressure washer has had this issue since day one... and the one i owner before this one had the same issue. I have to press and release the trigger 5-15 times and cycle it when i first fire it up. After that it works just fine.

I thiought this was normal.. as 2 different makes have done it.
 
   / pressure washer issues #10  
I have owned pressure washers for more than 40 years, and as soon as the engine is turning, the pump is pumping.

My pressure washers are 2500 psi to 3500 psi units.

If you just open the trigger with the engine off, you will get some water from the nozzle.

If the unloader sticks open, the water will recirculate, and if the loader sticks closed, it will shut off the pump. There is a spring that try's to keep the unloader closed and theredore pressure.

I have 4 pressure washers at this time, and one of them needs a new unloader valve, as you can start the engine with the trigger pulled, but as soon as you release the trigger, the water has no place to go, unloader valve stuck closed, and the engine will stop or blow something up, just like hydraulics if you try and stop the flow.

You can try and clean up the unloader seat and plunger, or just replace.

That is my story and I am sticking to it.
 
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