I turn the key, only a buzzing sound. Hooked up charger, battery had almost discharged but came back quickly. Still, only a buzz when key is turned. It is in neutral with both break pedals depressed. Tried chargers assist start, still only a buzzing sound. What does this sound like?

This tractor had been on a dealers lot that went out of business and only had 18 hours on it. I e-mailed Dealer I bought it from to see what he says, but wanted to post here for any suggestions.

Thanks! Very frustrated. Rob