“What would a potential buyer want to know that I could pretty easily find out for them so they could evaluate it?”
These might be some typical questions a potential buyer might ask. I’m sure there’s others too but these might be the basics.
What’s the year and HP? How’s the compression? Do you know the history of the motor? Last time it ran? Does it need work to run? If so, what? Does anybody still work on them? Can you still get parts? Where to get parts? How much does it weigh?