Re: Power washer unloader problem?
I believe I had the same PW (Excell). Same engine and pump was all aluminum. Had exact problem you describe. Un-loader looked identical too, I tried adjusting (mine had screw in end). After much tinkering and a blown hose (Weird setup off bottom of pump), while adjusting to high. I removed damaged hose which must have been a safety of sorts, then installed a pipe plug (same size as hose fitting). Lowered-backed out-un-loader, started machine with trigger pulled as you describe. I adjusted pressure slowly while releasing trigger to ensure it unloaded. I raised to what I thought was good pressure. It unloaded without issue for the remaining time I owned it. I sold to a friend explaining what I did and he still runs it today without issue to my knowledge. I have no good explanation why it worked well after replacing that hose with a plug but it did. Probably not the safest fix but it worked.
I've since bought a rigid unit with an oil lubricated pump, it is a much nicer unit than the old one.
I'd buy the replacement pump and hopefully you can get old one off. Not sure if shaft will accept new one?