Karcher 4 pulsing when trigger pressed not pulsing other wise.

David Koss

• 102 Answers
• Posted on Mar 15, 2009

SOURCE: the motor is pulsing on and off without the trigger being pressed

It is probably sucking air on one of the connections or around one of the fittings at the regulator. You can also turn the pressure up allittle on the regulator, that might stop it also. Make sure the clamps on the hoses going to the regulator is tite. Also it could be that the regulator is just bypassing water and if it has air in it it will pulsate.

SOURCE: pulsing and lost pressure

depending on amount of use i have found failures of the piston spring and retainer which are located inside main housing of pump,these cause pulsing and no pressure,you need to remove pump head and face plate to get to them,hope this is of help

SOURCE: Karcher/Winner 11 - motor pulses when hose is not operating

Hi, I had the same problem, Replaced the O rings and the rubber seals and cups inside the pressure washer and eventually the hose itself burst. Turns out the hose was leaking, internally between the inner sheath and the outside plastic cover, for quite some time and this caused the pulse. New hose and pressure cleaner is as good as new.

SOURCE: My Karcher 2.99 starts and stops, (pulses) when th...

Is liquid leaking from the base, when the Pressure washer is on ?
I have the same Problem, the leak is from the seam of the Manifold housing. There is a small crack in the seam. A manufacturing defect.. A New Manifold Complete Replacement is $61.03, about the half the price what I paid for this pressure washer at Walmart... :( If under 1 year old, and you can find a receipt,Karcher will replace the whole Pressure washer under warranty.

SOURCE: My Karcher pulses when on standby,stops when i use

Is there a leak from the bottom ?
If so Problem, the leak is from the seam of the Manifold housing. There is a small crack in the seam. A design weakness.. A New Manifold Complete Replacement approx. $61.03.
If not you may replace the Pump Manifold Housing from Karcher, or locate a local Karcher Service Center.
If under 1 year old, and you can find a receipt,Karcher will replace the entire Pressure Washer under warranty.