Yamaha Outboard Motors Factory Service Manual F6 and F8, Page 360Get this manual
BACKLASH Backlash indicator: YB-0626590890-06706 Magnet base: YU-3448190890-06705 Magnetic base attaching plate: YB-0700390890-07003 Dial gauge stand: YU-0309790890-01252 (5)While pulling the drive shaft downward, slowly turn the drive shaft clockwise and counterclockwise then measure the backlash when the drive shaft stops at each direction(6)Determine the shims to be added or removed according to the specifiedReverse gear backlash Less than 1.01 mm (0.0398 in) Shim thickness To be decreased by (1.2Measurement) 2.52 To be increased by