2007-2009 Yamaha F15/F20 Outboard Service Manual, Page 168Get this manual
Lower unit
Disassembling the lower case
1Remove the taper roller bearing outer race and forward gear shim(s)
Checking the pinion and forward gear
1Check the teeth of the pinion, and the teeth and dogs of the forward gearReplace the pinion or forward gear if cracked or worn
Checking the bearing
1Check the bearingsReplace if pitted or if there is rumbling
Checking the drive shaft
1Check the drive shaftReplace if bent or wornS6AG6660
2Measure the drive shaft runoutReplace if above specification
NOTE: Fit the hooks of the puller claw into the slots in the lower caseSlide hammer 1: YB-06096 Bearing puller legs 2: YB-06523 2Remove the needle bearing from the lower caseDrive shaft runout limit: 0.5 mm (0.0197 in)