Honda pressure washer cuts out when lance trigger released.

You most likely need to set your valve clearances. If it is hard to pull over or the recoil snaps back after starting your valves need to be set for sure. This may not be the entire problem but it is a good start. Also change the spark plug, a bad plug will cause odd problems and is too cheap not to eliminate as a source. In addition check your fuel, pour a little out into a white container (I like spray paint can caps for this) and look at the color. If it is yellow to orange it is bad. You can pour it into you car, the car electronic sensors will compinsate for it quality but a small engine can't. Use a NGK BP6ES or BPR6ES plug.
You need:
Feeler gages
10mm open end wrench
14mm open end wrench
1 long shaft screw driver or rod
1 spark plug socket and ratchet

Remove the spark plug and the valve cover. Pull the recoil over slowly until the intake valve opens (intake is closes to the carb and it will go down when it opens). Now put your long screwdrive down the spark plug hole. Slow pull the engine over until the screwdriver handle is at it highest point, this is top dead center. It may take a few attempts. Now check your valve clearance between the rockers and the top of the valve. The intake should be .006 and the exhaust .008, both can be +/- .001. To adjust: hold the large nut with the 14mm then loosen the small one with the 10mm. Lefty loosey. Now turn your large nut until you get the correct setting and then tighten the small one the lock it in. It may take a few attempts and alway reverify your setting after you lock it down. Once done, find top dead center again and reverify. Now your valves are set.