Yamaha 20C Service Manual page 206

LOWR
ASSEMBLY AND ADJUSTMENT
4) Install the dial gauge on the dial gauge stand
and install it on the gear case.
Install the backlash indicator rod on the drive
shaft and bring the dial gauge stem into contact
with the mark on the indicator rod.
Forward gear
1) Place the shift-rod in neutral.
2) Install a bearing-housing puller in the bearing-
housing, to engage with the centre bolt of the
propeller shaft.
3) Slowly turn the drive-shaft in and out, and read
the dial-gauge when the shaft stops in each
direction.
Reverse gear
1) Place the shift-rod in neutral.
2) Install a propeller on the propeller shaft, with
the front side facing backward, fit the nut and
tighten.
3) Slowly turn the drive-shaft in and out, and read
the dial-gauge when the drive-shaft stops in
each direction.
Selection of shims
The backlashes of the forward and reverse gears
are as follows:
<Standard backlash>
Forward gear
Reverse gear
6-13
E
0.20 – 0.50 mm
(0.0079 – 0.0197 in)
0.70 – 1.00 mm
(0.0276 – 0.0394 in)