After a running for a short while, the pressure starts pulsing, with an intermittent jet of water. Has anybody had the same problem and managed to fix it?
Thanks

Nick, November 2008

I had same problem, very common. Can be several problems. See manual trubleshooting, can get from Karcher online for free. My problem was caused by a tiny piece of sand stuck in the nozzle. Easy fix- remove six star head screws and separater plastic covers. Then pull out the plastic nozzle. The plastic nozzle is two pieces that can be further separated if needed. Take a SMALL pin and clear the obstruction. My sand was clear as glass and so was hard to see, but pin pushed it out. Wash it out so it dosn't get stuck in there again; reassemble. Also, water intake does have a filter (again, see manaual). Pull out hose washer, then pull out filter with neddle nose pliers.

E Beck, May 2010

Check your water pressure to the washer, if it is low due to local settings on the day then it will cause the washer to pulse

Laurie, December 2008

hi, im paul and ive got a 620M and have had it for several yrs. so far most problems are usually associated with a faulty o ring somewhere. just take the chance and open it up and find orings in the hose line and where the lines fit into the machine. 9 out of 10 times ive fixed it there. and dont waste money on genuine karcher orings. just get what u need at the hardward store. karcher charges an arm and a leg for o ring kits. there is a red thing in the water inlet i think it is and it screws out. take it out and check there too. hope ive been some help mate.

paul in oz, December 2008