1991 Yamaha Outboard Factory Service Manual 9.9 and 15 HP, Page 98Get this manual
GEAR CASE ASSEMBLY
Always use new gaskets, oil seals and O-ringsThe use of any used oil seal or O-ring may result in oil leakage due to invisible scratches or stretchesApply grease to parts where specified
Gear case 1I nstall the needle bearing Install the needle bearing plate on the driver rod so that the stamped mark faces upwardNext, screw the attachment into the driver rod, and install the needle bearingAfter installing the needle bearing, remove the needle bearing plate, and install it so that its stamped mark faces downwardNext, install the other needle bearingBe sure that the stamp mark on the bearing faces upward