1991 Yamaha Outboard Factory Service Manual 9.9 and 15 HP, Page 95Get this manual
Measuring the backlash of forward gear 1Install the forward gear in the forward gear bearing model by using the propeller shaft assembly (with the bearing housing O-ring removed) as guideRemove the prop shaftDetermine the shimming required to adjust the distance to 1.2mmUse the following graph to find the correct shimming III
23Measurem ent (mm)
0.8 0.9 1.0 1.1