Looking for ideas. Trying to help a friend with a Honda Pressure Washer and from the looks of it hardly used. When I got it there had been a significant mouse infestation so I pulled flywheel and cleaned out all mouse nest/debris.
- replaced fuel
- new spark plug and ignition coil (which had been chewed on). Spark test shows spark.
- I was able to get it started briefly with starter fluid, but wouldn’t keep running. Figured it was carb problem, but I cleaned it out multiple times and still nothing.
- Checked rocker arms / looked good and gaps were fine on combustion and exhaust sides.

Completely stumped at this point. Any advice?

Loosen the float bowl and see if your getting fuel to the carb.
 
Does the machine have a fuel pump?
 
Did you remove / clean the little jet located under the idle stop screw?
 
There's a small, black "spacer" that'll come loose when the screw is removed.
Under that is a black plastic and brass jet with an extremely small jet.
 
You can use a wire, cut off from a wire brush (held with a vise grip) to get it clean(it's that small).