It does look as if the belt pulleys have been incorrectly assembled. The illustrated parts list shows two different configurations for the model 33: 330026, which was chain drive; and 330413, which was belt drive. Yours is obviously 330413 since it is belt drive. I am doubtful that the large hex nut on the inboard side of the top (engine shaft) pulley belongs there. Also, there are parts on the inboard side of the cutter pulley that don't seem to belong either. It looks as if someone may have deliberately spaced the two pulleys outward for some reason, but the two idlers may not be cooperating with this. I suggest you look carefully at the illustrated parts list and assemble your mower exactly in conformity with it.
