Yamaha F100B F100C Outboards Factory Service Manual, Page 194Get this manual
Lower unit
Depth c: 187.6188.6 mm (7.397.43 in) 2Install the sleeve, original shim(s), and drive shaft bearing outer race
Checking the lower case
1Check the skeg and torpedo for cracks or damageReplace if necessary
CAUTION:
Add or remove shims, if necessary, when replacing the pinion or lower case