Who makes Stanley pressure washer motors - Stanley Garden

The valve-o-rings + [ parbaks seals ] where the pressure can be adjusted with.
Control the water inlet filter or hose that there are no waterlock couplers are used or is mounted
on the wrong site on the hose , that it is used as water inlet on the tap.

It sounds to me that there is air in the pump, remove the nozzle if possible and pull trigger until the air works thru the pump.

SAE 30W non detergent is advised by Stanley Dewalt

For safety reasons work on mains voltage switches must be preformed by a qualified electrician.

Disconnect the wand from the washer if you get water coming out of the discharge, the problem is in your wand or the line is plugged going to the wand.

There is a spring in there that makes it recoil. It has probably broken. Depending on who made the engine you can get a replacement for the whole assembly. A small engine shop should be able to replace it for a not a lot of money.

The pump will cycle on/off but if it works properly when you pull the trigger and it keeps working then its working correctly.

Did you figure this out yet? If not.

Did you check the onboard GFI breaker switch?
Did you make sure the water was connected and turned on?

Check for any missing washers or seals or check to see if they're not broken.

The female hos bib connection should have a typical hose washer inside.Often you can't tighten the nut tight enough without this washer, to keep it from leaking both from the hose, and the rest fo the fitting into the washer.