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

LOWR

Selecting the forward gear shim

1. Turn the taper roller bearing outer race
1 2 or 3 times to seat the rollers, and
then measure the bearing height (M5)
and (M6) as shown.
NOTE:
• Select the shim thickness (T2) by using the
specified measurement(s) and the calcula-
tion formula.
• Measure the taper roller bearing at 3 points
to find the height average.
Shimming plate 2: 90890-06701
Digital caliper 3: 90890-06704
2. Calculate the forward gear shim thick-
ness (T2) as shown in the examples
below.
6-57
Lower unit
A – 3
b
NOTE:
"R" is the deviation of the lower case dimen-
sion from standard, and "A" is the deviation of
the propeller shaft housing dimension from
standard. The "R" mark a is stamped on the
trim tab mounting surface of the lower case,
and the "A" mark b is stamped on the pro-
peller shaft housing in 0.01 mm units. If the
"R" mark or "A" mark is unreadable, assume
that "R" and "A" are zero and check the back-
lash when the unit is assembled.
Calculation formula:
Forward gear shim thickness (T2) =
8.45 + R/100 – A/100 – M5 + M6
Example:
If "M5" is 22.95 mm and "M6" is 15.73 mm
and "R" is (–1) and "A" is (–3), then
T2 = 8.45 + (–1)/100 – (–3)/100 – 22.95 + 15.73 mm
= 8.45 – 0.01 + 0.03 – 22.95 + 15.73 mm
= 1.25 mm
If "M5" is 22.95 mm and "M6" is 15.73 mm
and "R" is (–1) and "A" is (+2), then
T2 = 8.45 + (–1)/100 – (+2)/100 – 22.95 + 15.73 mm
= 8.45 – 0.01 – 0.02 – 22.95 + 15.73 mm
= 1.20 mm
B
S69J6625
6P23H11