Backlash; Measuring The Forward And Reverse Gear Backlash - Yamaha F25C Service Manual

LOWR
3. Calculate the reverse gear shim thick-
ness (T2) as shown in the examples
below.
NOTE:
"R" is the deviation of the lower case dimen-
sion from standard. The "R" mark a is
stamped on the anode mounting surface of
the lower case in 0.01 mm units. If the "R"
mark is unreadable, assume that "R" is zero
and check the backlash when the unit is
assembled.
Calculation formula:
Reverse gear shim thickness (T2) =
80.00 + R/100 – M2
Example:
If "M2" is 78.79 mm and "R" is (–1), then
T2 = 80.00 + (–1)/100 – 78.79 mm
= 80.00 – 0.01 – 78.79 mm
= 1.20 mm
4. Select the reverse gear shim(s) (T2) as
follows.
Calculated numeral
More than Up to
0.99 1.10
1.10 1.20
1.20 1.30
1.30 1.32
Available shim thicknesses:
1.0, 1.1, 1.2, and 1.3 mm
6-27
Lower unit
a
+5
+5
-1
S6D56430
Shim size to
use
1.0
1.1
1.2
1.3
Example:
If "T2" is 1.05 mm, then the reverse gear
shim is 1.0 mm.
If "T2" is 1.20 mm, then the reverse gear
shim is 1.1 mm.

Backlash

Measuring the forward and reverse
gear backlash
1. Remove the water pump assembly.
2. Set the gear shift to the neutral position
at the lower unit.
3. Install the special service tools so that it
pushes against the propeller shaft.
NOTE:
Tighten the center bolt while turning the drive
shaft until the drive shaft can no longer be
turned.
Bearing housing puller claw S 1:
90890-06564
Stopper guide plate 2: 90890-06501
Center bolt 3: 90890-06504
4. Install the backlash indicator onto the
drive shaft (16.0 mm [0.63 in] in diame-
ter), then the dial gauge onto the lower
unit.
6
6D55F11