Yamaha F100B F100C Outboards Factory Service Manual, Page 166Get this manual
Lower unit
2Install the original shim(s) and taper roller bearing outer race
Checking the lower case
1Check the skeg and torpedo for cracks or damageReplace if necessary
S60C6235
CAUTION:
Add or remove shims, if necessary, when replacing the forward gear or lower caseBearing outer race attachment 4: 90890-06620 Driver rod LL 5: 90890-06605
Assembling the lower case
1Install the needle bearing into the lower case to the specified depth