1991 Yamaha Outboard Factory Service Manual 9.9 and 15 HP, Page 111Get this manual
4 Insert the through-bolt and tightenMount the pinion, spring, and pinion stopper on the armature shaftUsing pliers, slightly open the clipHold the pinion stopper with your hand and fit the clip in the clip groove in the armature shaftNext, tighten the clip using pliersMake sure the cI ip fits tightly into the pinion stopper