His picture of the battery doesn't go far enough to the right. He said he burned a hole in the hood so that is probably where the positive clamp contacted the hood. The entire tractor looks like someone spray painted everything, but removed the decals, masked them off or bought new. Jack, at this point you need to replace the positive and negative battery cables (along with the correct battery), clean up all of the connections at the starter, and be sure you get a red cable for your positive.
Edit to add: When you buy used you should expect you're buying some problems and be prepared and able to deal with them. Old tractors never die. Their owners just get tired of resuscitating them.