Yamaha F200B Service Manual page 418

LOWR
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
and ball bearing. See steps 3 and 4 in
"Assembling the propeller shaft housing
assembly" (8-18).
TIP:
• If the original shims are missing, install new
shims with a combined thickness of 1.25
mm.
• Do not reuse a shim if deformed or
scratched.
2. Install the propeller shaft assembly (with-
out the dog clutch) and propeller shaft
housing assembly (without the O-ring).
See steps 2–4 in "Installing the propeller
shaft housing assembly" (8-29). (F200B)
See steps 2–4 in "Installing the propeller
shaft housing assembly" (8-35). (F250G)
TIP:
When assembling the lower unit to measure
the backlash, do not install the dog clutch
and O-ring.
3. Check that the
smoothly.
4. Measure the reverse gear backlash. See
steps 17–20 in "Measuring the forward
gear backlash and reverse gear backlash
before disassembly" (8-40).
Reverse gear backlash:
0.23–0.88 mm (0.0091–0.0346 in)
8-55
Lower unit
drive shaft turns
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. See "Removing the propeller
shaft housing assembly" (8-16). (F200B)
See "Removing the propeller shaft hous-
ing assembly" (8-22). (F250G)
2. Remove the reverse gear. See step 1 in
"Disassembling the propeller shaft hous-
ing assembly" (8-16).
3. Measure the thickness of each original
reverse gear shim in 2 places.
TIP:
Do not reuse a shim if deformed or
scratched.
4. 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" (8-57).
Example:
Backlash measurement (BL2) = 0.95 mm a
Reverse gear shim (T2) thickness adjustment
= 0.34 mm b
The current shim
increased by 0.34 mm.
thickness must be