Selecting The Reverse Gear Shim - SELVA MARINE Blue Whale 250 EFI Service Manual

LOWR
2. Calculate the forward gear shim thick-
ness (T1) as shown in the examples
below.
NOTE:
"F" is the deviation of the lower case dimen-
sion from standard. The "F" mark a is
stamped on the trim tab mounting surface of
the lower case in 0.01 mm units. If the "F"
mark is unreadable, assume that "F" is zero
and check the backlash when the unit is
assembled.
Calculation formula:
Forward gear shim thickness (T1) =
29.50 + F/100 – M1
Example:
If "M1" is 29.10 mm and "F" is (+5), then
T1 = 29.50 + (+5)/100 – 29.10 mm
= 29.50 + 0.05 – 29.10 mm
= 0.45 mm
If "M1" is 29.10 mm and "F" is (0), then
T1 = 29.50 + (0)/100 – 29.10 mm
= 29.50 + 0 – 29.10 mm
= 0.40 mm
3. Select the forward gear shim(s) (T1) as
follows.
Calculated numeral
at 1/100 place
1, 2
3, 4, 5
6, 7, 8
9, 10
6-25
Lower unit
Rounded numeral
0
2
5
8
Available shim thicknesses:
0.10, 0.12, 0.15, 0.18, 0.30, 0.40, and
0.50 mm
Example:
If "T1" is 0.45 mm, then the forward gear
shim is 0.42 mm.
If "T1" is 0.40 mm, then the forward gear
shim is 0.38 mm.

Selecting the reverse gear shim

1. Turn the ball bearing 1 2 or 3 times, and
then measure the bearing height (M2) as
shown.
NOTE:
• Select the shim thickness (T2) by using the
specified measurement(s) and the calcula-
tion formula.
• Measure the bearing outer race at 3 points
to find the height average.
Shimming plate 2: 90890-06701
Digital caliper 3: 90890-06704
2. Calculate the reverse gear shim thick-
ness (T2) as shown in the examples
below.
6P23H11