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Karcher k4 Anyone know anything about Kerchers ?

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flynnboy

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Hi, My karcher k4 is suddenly playing up ? When switched on it is making a pulsating noise until I operate the nozzle then it works fine. But, every time I stop using the nozzle the pulsating noise starts again. Anyone know anything about this ?

Thanks.
 

Spectric

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Sounds like a PRV, if it is beyond help and you end up looking for a new washer then look at Nilfisk as they are in my opinion a much better product.
 

Sandyn

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any signs of leaks anywhere?
This often causes pressure washer to pulsate. It doesn't need much of a leak for it to happen. The motor is controlled by a pressure switch in the output side of the pump. When you pull the trigger to start the washer, the output pressure drops, starting the motor. When you release the trigger to stop the washer, the washer runs on until a pressure switch is triggered to stop the pump. If there is a tiny leak, the pressure drops, motor starts, pressure increases, motor stops, water leaks, pressure drops, motor starts. The system pulses. The leak could be caused by frost damage inside the pump housing, so check for water coming out of the bottom of the unit.
 

minilathe22

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I would agree it sounds like the pressure valve, if you are lucky there is just some dirt in the valve and it will clean out. But the power washer will probably still work fine to be honest.
 

Yorkieguy

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Pulsating Karchers is a common problem after a few years use. I don't doubt that many have been needlessly consigned to the tip. The problem will be the cylinder head valve. and replacement is fairly straightforward. The parts are available from the likes of E-Spares and Amazon, and cost around £20.00. There are numerous videos on how to strip down and replace the defective valves.

This one is quite comprehensive:

How to Repair a Karcher Pressure Washer either K3 & K4, with Loss of pressure or surging or pulsing. - Bing video

Also, 2.42 mins into this e-spares video:

(27) How to Diagnose Pressure Washer Pump Problems - YouTube

This one might help too:

(27) How to Disassemble and Reassemble the Pump on a Karcher Electric Pressure Washer - YouTube

I repaired mine about three years ago and it still works fine. I suspect that the reason it failed was that I stored in in a garden shed and residual water in the pump froze over winter. Since repairing it, I've stored it on my garage and have had no problems. Just a small point about apparent low pressure: Remember that the lance is adjustable when when handling it, it's easy to inadvertently turn the flow from max to min.

Hope that helps.

Good luck with it.

David.
 

Fergie 307

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Agree wholeheartedly with David. Exactly the same for me, now make sure it is properly drained out before storing and keep it somewhere it can't freeze. Never had a problem since.
 

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