My best score was a 6500W generator that someone just dumped at the transfer station, no idea if it was good or not but scrap alone would be worth a few bucks so I wrested it into my truck. Got it home and started diagnosis...turned out the needle and seat in the carb had stuck open and filled the motor with fuel...guess they went to use it and it was hydro-locked and assumed it was junk so tossed it. Drained the oil and fuel, let it air out for a day or two, pulled the carb apart and cleaned everything, some fresh oil and fuel and it fired right up!
Now I have a generator panel in my house and it runs the well, furnace, fridge, some lights and a few outlets!