9-tooth drive gear.Fits: Select Mercury 2.5 DFI, 200 HP V6 DFI, 225 HP V6 DFI, 3.OL V6Replaces: Mercury 50-833153, 50-833153-1, 50-833153-2, 50-833153-3, 50-833153-4, 50-833153-5, 50-898265008, Sierra 18-6283