Pressure washer has recently started pulsing-its like a lack of water but not-at least i think not-when top is removed from lance it seems okay but when put back on it starts 'pulsing' any advice please jim newcastle

sounds like your unit has a bypass problem either needs adjustment or replaced

This fault is within the control head, under the detergent valve is a small spring loaded valve that acts to induce the detergent, this will have failed, the shaft of the component breaks off the disk base leaving a small hole in the centre of the disk. This is enough to allow pressure past the component. The machine will pulse when operated and will not induce the detergent. I've looked everywhere to find this part as I have a karcher with the same fault.

HI it sounds like you may just have a blocked jet on the end of your lance. Please remove and clean.

None of these fixes works for me and the original poster, like me what he's saying is when he swaps the high pressure lance for the patio attachment it pulses on and off, but when that happens, you can swap back to high pressure lance and it's fine. This means it's the patio attachment not any valves or power source, I have the same problem

hello,

Try remove the front half of your lance and with the water hooked up and on full try pull your trigger a few times on and off... Then try start the engine if it doesnt go with the trigger off try start it with the trigger pulled on... then replace the front half of your lance and see it the pressure is there now.

Sometimes this can loosen a stuck bypass valve otherwise if it is stuck bad then it will have to be stripped down and cleaned up

Hope this helps

Brad

hi it sounds to me like you have the wrong lance nozzel in remove the lance and try then, regards

try this
dissconect hose and lance , and check for water flow through the machine , if theres none or just a trickle then you may have gunk in your inlet filter ( usually a small plastic gauze insert just where the water feed hose connects )
then start machine , check for high pressure flow ( you will see the difference )
its quite common for the nozzle on the lance to become blocked
if all this seems fine but the lance is vibrating then you have a blockage in one or more of your pump valves .

Dear Osville,
It is not clear what type of lance or nozzel you have. You said that the machine works fine with the circulating water jet(the turbo). So it seems the machine is fine. I do sometimes service variable nozzels and variable lances. But the best solution is to replace nozzels and variable nozzles and lances with new ones. Regarding the fan spray setting it could have no pressure because it might be in the chemical setting. The chemical setting lets out a fan shape flow of water, but with less pressure. The chemical system only works on low pressure in domestic washers, that is why it needs a low pressure flat spray. The pencil jet has 2 jets comming out because if it is a lance or nozzel with ball bearings, these ball bearings must have stuck in a wrong position. Also 2 jets can come out, due to a damaged nozzel hole.
Altogether, the best advice is to buy a new nozzel or lance...which ever your machine uses. All Karcher machines have their own specific nozzels, lances and high pressure hoses. You cannot change these from one model to another.
Regards,
Fulltech.

you have a restriction in the nozzle end of the lance. clean with paper clip.
if not you have some dirt in the pump head valves which need cleaning

it will switch from hot to cold and back and forth trying to regulate the temp. You probrbly have more pressure in your cold water line than your hot or vise versa. This will cause it to seem to pulse. Dave www.washermd.com