Yamaha F90D Service Manual page 148

LOWR
4. Install the backlash indicator onto the
drive shaft (20 mm [0.79 in] in diameter),
then the dial gauge onto the lower unit.
NOTE:
Install the dial gauge so that the plunger a
contacts the mark b on the backlash indica-
tor.
Backlash indicator rod 3:
YB-06265
Backlash adjustment plate 4:
YB-07003
Dial indicator gauge 5: YU-03097
Magnetic base stand 6: YU-A8438
5. Slowly turn the drive shaft clockwise and
counterclockwise and measure the back-
lash when the drive shaft stops in each
direction.
Forward gear backlash:
0.28–0.63 mm (0.0110–0.0248 in)
6. Add or remove shim(s) if out of specifica-
tion.
Forward gear
backlash
Less than
0.28 mm (0.0110 in)
More than
0.63 mm (0.0248 in)
M: Measurement
6-29
Lower unit
Shim thickness
To be decreased by
(0.46 – M) × 0.56
To be increased by
(M – 0.46) × 0.56
Available shim thicknesses:
0.10, 0.12, 0.15, 0.18, 0.30, 0.40, and
0.50 mm
7. Remove the special service tools, and
then install the water pump assembly.
6D81G11