1991 Yamaha Outboard Factory Service Manual 9.9 and 15 HP, Page 118Get this manual
Sheave dru and starter rope 1Turn the sheave drum so that the cut on the outer surface of the sheave drum faces toward the starter handle2Pass the starter rope through the cut 5Remove the nut and bolt at the center of
the starter case and then remove the sheave drum from the starter caseWhen removing the sheave drum, hold down the starter spring with screwdriver inserted into the hole in the sheave drum so that the starter spring will not spring out