Yamaha Outboard F15A F9.9C, FT9.9D F15 Service Manual, Page 302Get this manual
PROPELLER SHAFT HOUSING ASS'Y (F15AF9.9C)
2Install: Oil seals Oil seal depth a: 3.03.5 mm (0.120.14 in) Oil seal installer 1: (Needle bearing attachment) N.A90980-06614 Driver rod 2: YB-0607190890-06604
First, fully install the lower oil seal and then the upper
3Install: Ball bearing