Small Engines (Lawn Mowers, etc.): engine not running well, honda pressure washer, stroke engine

Question
I have a honda pressure washer with a GC160 four stroke engine.  The engine will crank easy but won't run evenly.  The engine will almost shut down when I pull the trigger to pressure wash.  The inlet screen is clean, the air filter is clean and the plug looks good.  the pressure washer is fairly new--three years old.  Seems like it ain't gettin enough gas?  What do you think?

Answer
Hi Glen
Sorry for the delay, vacation -

1- Replace the plug, regardless of how it looks
2- Drain and flush the tank, put in all fresh gas.
3- Run some pressure washer pump lube through the system to make sure the unloader valve isn't sticking.

Do this and lemme know how it goes.