Karcher Pressure wash pulsating!

Karcher Pressure wash pulsating!

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Blackpool Rocker

Original Poster:

381 posts

221 months

Saturday 26th February 2011
quotequote all
..I have a small Karcher pressure washer that I use to clean the car. It works a treat with plently of pressure, however, as soon as I let go of the trigger the motor instead of stopping, it 'pulsates' at about every second interval.

There is no water leaking from the jet wash or air leaking into the water supply. I have looked to see if there is a inline filter,but carnt see anything. Is it time
for a new pressure washer...?

PJ S

10,842 posts

226 months

Saturday 26th February 2011
quotequote all
Sounds like an electrical issue, but best have a chat with Karcher or a local PW retailer who'll know if it's a common fault/easy cheap fix.
Chances are though, it's not cost effective to be looked at, in which case it's time to replace.
I've always been one for buy once use often, which generally means investing a decent sum at the outset, but that might not be viable for you - only you'll know the score on that front.

Karcher's machines aren't anything to write home about, until you're spending £300+ and even then.....
Depending on budget, Nilfisk/Alto Kew, Makita, and Stihl would be where I'd be directing your attention, and as a Makita HW131 owner, I can't sing it's praises highly enough.
Stonking machine, and pretty much on a par with the more expensive Kranzle.

Laser Sag

2,860 posts

242 months

Saturday 26th February 2011
quotequote all
Worth trying a different lance on the unit, mine did this and I was told it was the motor, changed the motor and it still did it turned out the lance wasnt sealing properly couldnt see any leak but put new lance on and all was fine.

mad4amanda

2,410 posts

163 months

Saturday 26th February 2011
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Mine does that when the water supply is interupted by say a kink in the hose

pikey

7,698 posts

283 months

Saturday 26th February 2011
quotequote all
mad4amanda said:
Mine does that when the water supply is interupted by say a kink in the hose
Mine too.

Is always the cause.

Nedz

2,439 posts

173 months

Saturday 26th February 2011
quotequote all
I had a karcher that did this for years.I dont know what the cause was but it was nothing to do with low pressure or a kink in the hose.I used to turn it off when i let off the trigger as i found that if you left it pulsating for more than about 30 sec,it would stop working for a while(as well as sounding very annoying).

I used mine for work so it got an awful lot of hammer but it kept working fine so it might not be worth binning it yet as long as you dont mind switching it on/off while using.The frost eventually killed mine last january.

Blackpool Rocker

Original Poster:

381 posts

221 months

Saturday 26th February 2011
quotequote all
..I have tried a different lance but it still pulsates. The pressure washer was not over expensive, so i guess if I need a new one it doesnt owe me anything. Untill it finally packs up, I will just keep on turning it off.

CharlesElliott

1,991 posts

281 months

Saturday 26th February 2011
quotequote all
The cut off is pressure based - i.e. water pressure is above a certain level, the motor stops. So when you let go of the trigger the pressure builds and the motor stops. It could be a faulty pressure switch, but more likely there is a small leak somewhere. So the pressure drops slightly, the motor cuts in, then the pressure rises and it cuts out again. Repeat ad infinitum.....

JC2012

517 posts

215 months

Saturday 26th February 2011
quotequote all
I'd recommend a Nilfisk - About £70-80 in argos and if you have nectar points to spend then theres an added bonus . Has outlasted my Karcher by a long long way ! many friends who had karchers also complained of the same old pulsating one friend had one for a fortnight and it started doing it just not worth it.


Roop

6,012 posts

283 months

Saturday 26th February 2011
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Both my Kaerchers did the same thing. One within a month or so and the second within 18 months. I replaced it with a Mac Allister (B&Qs own brand I think), which amongst other things has a brass impeller rather than the nylon one in cheap Kaerchers. I think using hot water in my Kaercher (despite the temp being within spec) knackered something on the inside...

ahoythere

1 posts

144 months

Friday 30th March 2012
quotequote all
For what it's worth, my Karcher pressure washer also pulsates but only when the machine is switched on and I'm squeezing the trigger.

After a bit of Googling, I decided to unscrew the black hose inlet connector (the nozzle which slots into your hosepipe) to see if there was a blockage in the inlet pipe. Lo and behold, when I peered down the inlet pipe, I could see black deposits! Now here's the thing: it's not immediately obvious that there's a filter in the inlet pipe. On closer inspection however, I could see that there's a white plastic tube-shaped filter (about 2.5 - 3 ins in length) which slots inside the transparent inlet pipe. I managed to prise out the filter using a small flat-headed screwdriver. Once the filter was removed, I could see that it was partially blocked with debris. This may have constricted the water supply, causing the pump to switch off until there was a sufficient flow of water to make the pump kick in again.

I've flushed out the debris and slotted the filter back into the inlet pipe. You are probably dying to know whether this has solved the pulsation problem. Unfortunately, I haven't had time to connect my Karcher to a water supply yet, but I'm quietly optimistic...

Hope this helps.

RedSpiseeBalls

441 posts

158 months

Sunday 1st April 2012
quotequote all
said:
Mine too.

Is always the cause.
This, my nilfisk does the same thing

erich4898

1 posts

87 months

Friday 30th December 2016
quotequote all
ahoythere said:
For what it's worth, my Karcher pressure washer also pulsates but only when the machine is switched on and I'm squeezing the trigger.

After a bit of Googling, I decided to unscrew the black hose inlet connector (the nozzle which slots into your hosepipe) to see if there was a blockage in the inlet pipe. Lo and behold, when I peered down the inlet pipe, I could see black deposits! Now here's the thing: it's not immediately obvious that there's a filter in the inlet pipe. On closer inspection however, I could see that there's a white plastic tube-shaped filter (about 2.5 - 3 ins in length) which slots inside the transparent inlet pipe. I managed to prise out the filter using a small flat-headed screwdriver. Once the filter was removed, I could see that it was partially blocked with debris. This may have constricted the water supply, causing the pump to switch off until there was a sufficient flow of water to make the pump kick in again.

I've flushed out the debris and slotted the filter back into the inlet pipe. You are probably dying to know whether this has solved the pulsation problem. Unfortunately, I haven't had time to connect my Karcher to a water supply yet, but I'm quietly optimistic...

Hope this helps.
My daughter has the same problem as stated above, I am just about to go and sort it out for her. However the pulsing when you release the trigger is not due to the lack of water pressure as these washers are self priming and can be used from a water butt. It is the seals inside leaking the pressure back so the pressure switch kicks in when the build up of pressure drops. These are an easy fix but the cost of the seals, even on ebay are quite dear.

Winky151

1,267 posts

140 months

Friday 30th December 2016
quotequote all
erich4898 said:
My daughter has the same problem as stated above, I am just about to go and sort it out for her. However the pulsing when you release the trigger is not due to the lack of water pressure as these washers are self priming and can be used from a water butt. It is the seals inside leaking the pressure back so the pressure switch kicks in when the build up of pressure drops. These are an easy fix but the cost of the seals, even on ebay are quite dear.
If you get a chance could you post some pics of the seals that need replacing?

TIA

Big Al.

68,798 posts

257 months

Friday 30th December 2016
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I had the same problem it turned out to need a new push on lance knozzle. I found it only pulsed using the cone shaped tip (the one used for cleaning paving) with the spinning ball bearing. Called Karcher and they replaced FOC.

Tried the same lance tip on another Karcher Pressure washer and it did exactly the same.

anonymous-user

53 months

Friday 30th December 2016
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CharlesElliott said:
The cut off is pressure based - i.e. water pressure is above a certain level, the motor stops. So when you let go of the trigger the pressure builds and the motor stops. It could be a faulty pressure switch, but more likely there is a small leak somewhere. So the pressure drops slightly, the motor cuts in, then the pressure rises and it cuts out again. Repeat ad infinitum.....
This, I had something similar on my pressure washing that resulted in it blowing the 13A fuse, If there is a leak on the high pressure side the pressure washer sees this as the on signal. You need to disassemble and clean/fix the bypass valve on the pump to stop the leak

Higgs boson

1,091 posts

152 months

Friday 30th December 2016
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rondennis1

1 posts

68 months

Wednesday 25th July 2018
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My K2 leaked. Bought ebay pump (£30), then stripped and reassembled. No more leak! However, had same pulsing problem as above, so changed cone for lance nozzle, as advised. Problem solved!!! Thanks for your help!