Measuring The Reverse Gear Backlash; Adjusting The Reverse Gear Shim Thickness (T2) - Yamaha F30B 2018 Service Manual

b. Calculate the new forward gear shim (T1)
thickness.
TIP:
• Use the lowest number of shims to obtain the
required shim thickness.
• If the calculated shim thickness cannot be ob-
tained 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 =
Current 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 =
0.50 mm
Shim thickness adjustment = 0.20 mm
New forward gear shim (T1) thickness =
0.50 mm + 0.20 mm = 0.70 mm
Use the following formula when the shim
thickness adjustment value is negative.
Current forward gear shim thickness =
0.50 mm
Shim thickness adjustment = –0.17 mm
New forward gear shim (T1) thickness =
0.50 mm + (–0.17 mm) = 0.33 mm
Available shim thicknesses
Forward shims
0.10/0.12/0.15/0.18/0.30/0.40/
0.50 mm
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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" (8-20).
TIP:
• If the original reverse gear shims (T2) are
missing, install new shims with a combined
thickness of 0.50 mm.
• Do not reuse a shim if deformed or scratched.
2. Measure:
• Reverse gear backlash
See step 3 in "Measuring the forward gear
backlash and reverse gear backlash be-
fore disassembly" (8-27).
Out of specification  See "Adjusting the
reverse gear shim thickness (T2)" (8-36).
Reverse gear backlash
0.75–1.22 mm (0.0295–0.0480
in)
Adjusting the reverse gear shim thick-
ness (T2)
1. Remove:
• Propeller shaft housing assembly
• Reverse gear shim (T2)
2. Measure:
• Thickness of original reverse gear shim
(T2) in 2 places.
TIP:
Do not reuse a shim if deformed or scratched.
8-36
Shimming