Yamaha F100B F100C Outboards Factory Service Manual, Page 201Get this manual
Shimming (F100C) Shimming
NOTE: Shimming is not required when assembling the original lower case and inner parts Shimming is required when assembling the original inner parts and new lower case Shimming is required when replacing the inner part(s)2Install the pinion and pinion nut, and then tighten the nut to the specified torquePinion nut: 93 Nm (9.3 kgfm, 67 ftlb)
3Measure the distance (M) between the shimming tool and the pinion as shown
Selecting the pinion shims
1Install the drive shaft and drive shaft bearing to the shimming tools
NOTE: Measure the pinion at three points to find the clearance average
Digital caliper 4: 90890-06704 4Calculate the pinion shim thickness (T3) as shown in the examples below