I have a Karcher K3.99 it is pulsing when you release the trigger. I have tried to remedy it by letting water through it as per instruction from Karcher help desk. Still doing it how can i fix this and what is the problem
I have the exact same problem on the same model as well. I have taken it apart and there's nothing obviously wrong. Some say it's due to blocked lance (not in my case). Others say its due to overpressure for some reason.
Clive, March 2009
I have exactly the same model and the same problem, machine only 18 months old and cost £134. I have emailed Karcher, waiting to see if they reply, looks like a manufacturing fault.