Yamaha F75F - Measuring the Reverse Gear Backlash

Shimming
8-32
Example:
Backlash measurement (BL1) = 0.10
mm “a”
Forward gear shim (T1) thickness ad-
justment = –0.24 mm “b”
The current shim thickness must be
decreased by 0.24
mm.
b. Calculate the new forward gear shim
(T1) thickness.
• Use the lowest number of shims to obtain the
required shim thickness.
• If the calculated shim thickness cannot be
obtained with a combination of the available
shims, increase or decrease the shim thick-
ness by 0.01 mm.
Calculation formula:
New forward gear shim (T1) thickness
= Cu
rrent forward gear shim thickness
+ Shim thickness adjustment
Example:
Use the following formula when the
shim thickness adjustment value is
positive.
Current forward gear shim thickness =
0.72 mm
Shim thickness adjustment = 0.22 mm
New forward gear shim (T1) thickness
=
0.72 mm + 0.22 mm = 0.94 mm
Use the following formula when the
shim thickness adjustment
value is
negative.
Current forward gear shim thickness =
0.72 mm
Shim thickness adjustment = –0.24
mm
New forward gear shim (T1) thickness
=
0.72 mm + (–0.24 mm) = 0.48 mm
4. Install:
• Determined forward gear shim (T1)
• Tapered roller bearing outer race
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 mea-
surements 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:
• Reverse gear shim (T2)
• Propeller shaft housing assembly
See “Installing the propeller shaft housing
assembly” (8-16).
A. Backlash measurement (BL1)
B. Shim thickness adjustment
0 5 10 15 20 25 30 3
5
A
–0.30 –0.27 –0.24 –0.21 –0.18 –0.15 –0.13 –0.
1
B
0
.
30
0.20
0.10
0
–0.10
–0.20
–0.30
–0.40
0 5 10 15 20 25 30 3
5
B (mm)
A (1/100 mm)
a
b
Available shim thicknesses
Forward shims
0.10/0.12/0.15/0.18/0.30/0.40/0.50
mm