This sounds like an unfortunate series of events leading up to some buyers remorse. I guess you have to ask yourself if you are just plain sorry that you bought that tractor.
I guess I would talk to the manager some more, in as calm a manner as possible. Does your bill of sale say "as is, as shown"? If not then I think you have the right to make some assumptions. While you couldn't expect them to service the tractor unless you specified that in the agreement, change fluids, and filters, etc., I think that you could assume that they would pressure wash it, and check fluid levels, etc. I would also expect that they wouldn't use "your" tractor after the agreement, and deposit.
It's too bad that you waited some time to deal with it, but I can understand, given work pressures, and the excitement of getting the tractor. My state has a grace period after major purchases, to cover those situations where major items are bought under impulse, and then regretted, etc. Perhaps your state does too? Still, talking to the manager /owner is your best recourse. I would be as honest, and calm with them at this point as you would like them to be with you. Admit that you were upset, but talk towards a positive resolution of your situation. They really don't want to lose a customer, and they certainly don't want a bad taste about their dealership circulated on the internet, and in your area. You are in business too, think about how you would want a customer to deal with the things you are feeling, and also think about what you would be willing, or not willing to do for that person given the right approach. If you made a mistake, you don't have to tell us, but be honest with yourself.
Sorry if this sounds like preaching........ it is not. I have been guilty in the past of following the same road you are on, and learned that there is a better way, with fewer regrets.
