unloader valve and it seems fine. Nothing else is obviously wrong- nothing clogged, etc.

Is the next step to replace the pump? This pressure washer has an idle-down, so the pump is a little more expensive. But I found a 3rd party version for only $99 that might be worth a try.

The symptom is that the engine never revs up when you squeeze the trigger on the wand so just hose pressure water comes out. This is a Ryobi model with a Honda engine. 3000 psi or something like that.