1991 Yamaha Outboard Factory Service Manual 9.9 and 15 HP, Page 75Get this manual
SHIM ADJUSTMENT Preparation for adjustment Gear backlash Determining pinion gear position Measuring the backlash of forward gearMeasuring the backlash of reverse gear GI;AR CASE ASSEMBLY Gear case Bearing 110using Gear case cap Clutch dog, cross pin and shift spring Assembling the gear case unit Water pump installation