Yamaha F225F, Service Manual

Page: 436 / 576

8-57
LOWR
Lower unit
Measuring the reverse gear backlash
• Spray anti-rust lubricant on the gears and
bearings before installation. Do not apply
gear oil to the parts. Otherwise, correct
measurements cannot be obtained.
• Keep the parts free of foreign material,
such as dirt and lint.
• When measuring the forward gear or
reverse gear backlash, use the original
bearings and shims.
1. Install the original reverse gear shims,
propeller shaft assembly, and propeller
shaft housing assembly. See “Installing
the propeller shaft housing assembly” (8-
29).
TIP:
• If the original shims are missing, install new
shims with a combined thickness of 0.50
mm.
• Do not reuse a shim if deformed or
scratched.
2. Check that the drive shaft turns smoothly.
3. Measure the reverse gear backlash. See
steps 11–14 in “Measuring the forward
gear backlash and reverse gear backlash
before disassembly” (8-39).
TIP:
In the “Reverse gear shim (T2) selection
chart,” use the round-down average for the
backlash measurement (BL2).
Adjusting the reverse gear shim (T2)
thickness
1. Remove the propeller shaft housing
assembly, propeller shaft assembly, and
original reverse gear shims. See
“Removing the propeller shaft housing
assembly” (8-16).
2. Measure the thickness of each original
reverse gear shim in 2 places.
TIP:
Do not reuse a shim if deformed or
scratched.
3. Determine the reverse gear shim (T2)
thickness adjustment using the “Reverse
gear shim (T2) selection chart” according
to the backlash measurement (BL2) from
“Measuring the reverse gear backlash.”
See “Reverse gear shim (T2) selection
chart” (8-59).
Example:
Backlash measurement (BL2) = 0.10 mm
a
Reverse gear shim (T2) thickness adjustment
= 0.42 mm
b
The current shim thickness must be
increased by 0.42 mm.
A
Backlash measurement (BL2)
B
Shim thickness adjustment
Reverse gear backlash:
0.15–0.88 mm (0.0059–0.0346 in)
0.52 0.47 0.42 0 0 0
0 5 10 15 20 25 3
B
(mm)
0.60
0.40
0.20
0
0 5 10 15 20 25 3
A
(1/100 mm)
A
B
a
b