If buying used a Honda generator...what should I check?

I don't buy used, as even the prettiest shiniest unit can be a piece of worn out junk. There are tests that involve bore scopes and load testing that might give you a clue as to the units life. Even scuff marks are meaningless. I hauled a Honda generator for three years and thousands of miles. It looked rough, but did not have one hundred hours on it. We had others at work that hammered away for days at a time, got the oil changed, "once in a awhile", but looked good.

Be careful. Depending on your application, new can be a bargain.