Karcher K4.99 jet wash losing power and 'pulsing'

[peter2407]

I have a Karcher K4.99 jet wash, about 6 years old, only using once or twice a year for doing the drive, clean the boat etc. Recently, it has started to lose its 'oomph' (ie won't take moss off the drive, where before it would). It has also started to 'pulse' -where there used to be a continuous powerful jet no there is a weak intermittent jet. Can this be fixed? Are there service kits or similar available?

 

[LittleShip]

I would suggest (from past experience) that the water flow to the machine is inadiquate, or that you have some restriction on the hose.

Check that you dont have a one way valve fitted on the hose......

Tom

 

[Cymrogwyllt]

When mine did that it was traced to the corroding iron supply pipe in the driveway failing to let enough water through. Replacing the pipe sorted it. Quite a bit of fuss and expense 'as a try it and see'.

Might be worth checking how many litres a min the tap supplies. iirc a flow of about 8 to 10 l/min was needed for mine

 

[VicS]

A new cylinder head assembly will probably sort it out if the problem is not with the water supply

About £14 Google

May only be a valve not seating due to dirt/ debris in which case a good clean out will get it going

 

[Lodesman77]

Sounds like the spill valve has corroded, or the pressure valve in the wand has scaled up.

Take a look at http://www.m-and-d.com/karcher_parts.html for your model which will give you an exploded parts diagram which should help you to find the spill valve; strip it and clean it out or replace.

To descale the wand run some vinegar through using the detergent intake and leave it to sit for a while...