Why is belt smoking on sears tractor?

It is hard to give pinpoint answers because we don't have a lot of information to work with. Like when does this happen? Is it when you engage the blades or when you let up the clutch and try to get it to move. Chances are if you have a belt that is smoking it is one of these two things: The one thing I would imagine is that you have a idler pulley that is going bad. That is a pulley that the belt wraps around to keep tension on it. The next option would be that a spindle on the deck for one of the blades has locked up.