[davidlewispa]

Starts fine but after 30 sec of pressure washing it starts to knock and starts to lose pressure. i let go of the trigger and starts to run fine again. If I continue to hold the trigger it will knock until the engine stops. It will then start fine again. Oil level is fine. Any thoughts on a likely cause?

 

[tractornut]

I would try to run some detergent through it on low pressure just put some dawn in the inlet of the pump and then hook it up and run it see if that helps maybe something is partially plugged in the pump other than that it may need a new pump.

 

[Rent-A-Husband]

I agree. Sounds like a pump issue.