Yamaha F150B, Service Manual

Page: 356 / 458

8-77
LOWR
Lower unit
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 forward gear shim
thickness (T2) adjustment in the
“Forward gear shim (T2) selection chart”
according to the truncated average (BL2)
from “Measuring the forward gear
backlash.”
Example:
(BL2) = 0.55 mm
a
(T2) adjustment = –0.16 mm
b
from the
“Forward gear shim (T2) selection chart.”
The current shim thickness must be
decreased by 0.16 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.
4. Calculate the new forward gear shim
thickness (T2) as same way in the
example.
Calculation formula:
New forward gear shim thickness (T2) = Cur-
rent forward gear shim thi Shim
thickness adjustment
Example:
If the current forward gear shim thickness is
0.55 and the shim thickness adjustment is
–0.20 mm, then
(T2) = 0.55 mm + (–0.20) mm
= 0.55 mm – 0.20 mm
= 0.35 mm
TIP:
• Use the least number of shims to achieve
the required shim thickness.
• If the calculated shim thickness cannot be
obtained with a combination of the available
shims, increase the shim thickness by
0.01 mm.
5. Install the shim(s) (T2) and propeller
shaft housing assembly.
0.22 0.18 0.15 0.26 –0.12 –0.16 –0.19
0 5 10 50 55 60
0
0 5 10 15 50 55 60
0.20
–0.20
–0.40
–1.20
a
b
B
(mm)
A
(1/100 mm)
A
B
Available shim thicknesses:
0.10, 0.12, 0.15, 0.18, 0.30, 0.40, and
0.50 mm