Yamaha Marine Outboards Factory Service / Repair/ Workshop Manual 225G 250B L250B, Page 225Get this manual
BACKLASH (COUNTER ROTATION MODELS)
Measuring steps (1) Set the shift rod into the neutral positionShift rod wrench YB-0605290890-06052
(2) Install the backlash indicator onto the drive shaft (on the 22.4 mm (0.88 in) diameter portion of the drive shaft)Backlash indicator YB-0626590890-06706 (3) Install the dial gauge onto the lower unit and have the dial gauge plunger contact the mark on the backlash indicatorMagnetic-base plate2 YB-0700390890-07003 Dial gauge set YU-0309790890-01252 Magnetic base4 YU-3448190890-06705 (4) Set the lower unit upside down