1998-2006 Yamaha F20/F25 Outboards Service Manual, Page 233Get this manual
FORWARD GEAR AND DRIVE SHAFT
SERVICE POINTS
Forward and reverse gear disassembly 1RemovePinion gear nut Drive shaft holder: YB-06079-A90890-06517 Pinion nut holder: YB-0607890890-06505
2Remove: Pinion gear Forward gear (along with the tapered roller bearing)
3Remove: Drive shaft bearing outer race Pinion gear shim(s)