Yamaha F150B, Service Manual

Page: 322 / 458

8-43
LOWR
Lower unit
Measuring the reverse gear backlash
1. Install the shim(s) (T2) and propeller
shaft housing assembly. See “Measuring
the forward gear backlash” (8-38) step
9–step 13.
2. Measure the reverse gear backlash. See
“Measuring the forward and reverse gear
backlash before disassembly” (8-28).
Adjusting the reverse gear shim
thickness (T2)
1. Remove the propeller shaft housing
assembly and shim(s) (T2). See “Remov-
ing the propeller shaft housing assembly”
(8-10).
2. Measure the thickness of each original
shim(s) (T2) in 2 places.
TIP:
Do not reuse a shim if it is deformed or
scratched.
3. Determine the reverse gear shim
thickness (T2) adjustment in the
“Reverse gear shim (T2) selection chart”
according to the truncated average (BL2)
from “Measuring the reverse gear
backlash.”
Example:
(BL2) = 0.75 mm
a
(T2) adjustment = –0.15 mm
b
from the
“Reverse gear shim (T2) selection chart.”
The current shim thickness must be
decreased by 0.15 mm.
A
Backlash measurement (BL2)
B
Shim thickness adjustment
TIP:
• If the shim thickness adjustment value is
positive, the current shim thickness must be
increased by that amount and, if the value
is negative, the current shim thickness must
be decreased by that amount.
• The gray-colored area on the selection
chart indicates the range of the specified
backlash. Shimming is not required if the
measured backlash is within the gray-col-
ored area.
• The values for the shim thickness adjust-
ments specified in the selection chart are
intended to achieve the median value within
the range for the specified forward or
reverse gear backlash.
• The selection chart table shows the shim
thickness adjustments for marked points on
the chart.
Reverse gear backlash:
0.33–0.74 mm (0.0130–0.0291 in)
0.36 0.33 0.29 –0.15 –0.18
0 5 10 75 80
0.20
0
–0.20
–0.40
–1.20
0 5 10 70 75 80
A
(1/100 mm)
B
(mm)
A
B
a
b