At work we have a seldom-used Honda-powered pressure washer. Since I compulsively check dipsticks (I KNOW I have a problem...) I checked this one.
As soon as the dipstick was loose, a mix of gas and oil came flying out.
I walked the unit over to the shop and drained it. About 3 quarts of basically black gas came out.
I was curious to see how this would turn out, so I filled it up with HD30 (from a barrel that's been sitting in the corner for at least 8 years). I added some gas as the tank was empty. Much to my surprise, it started on the first full!
I suppose the float stuck, sending gas into the cylinder over the last few months.
I ran it for a while, cleaning the parking lot. I shut the gas off and ran the bowl dry; hopefully that will prevent problems down the road.