If this is anything like my noname pressure washer, there's a recirculating valve in the pump body, on the discharge side. It is supposed to sense very high discharge pressure (when you release the trigger) and route the pump outpyt back to the input. Thst way the pump doesnt lock solid and fry the motor when you stop squirting.
The fed from the hose feed still goes thru, just on tap pressure, giving a pathetic little dribble when you spray, despite the motor rinnung.
On mine the calve was integral with the pump and the washer was a Clallenger ir Champion; cheapo with minimal support.
Working on the assumption I had nowt to loise, I managed to carefully disassemble the pump, chean the valve innards and reassemble with a smear of Vasilene.
The jet in my lance was a bit clogged as well - not much but enough to fool the overpressure valve into operating a little early sometimes
It Took a while but it now works fine.
xxx, February 2016
