I was wondering if somebody might tell me the difference between a carb for a 1989 Evinrude 9.9 hp and a carb on a 1989 Evinrude 15 hp. I looked them up on a parts website and they are identical down to the same numbers. So I can't see where the difference is. Thats also the same in the intake and exhaust part #'s as well. Help! thanks Plmbr