Backlash (Regular Rotation Model); Measuring The Forward And Reverse Gear Backlash; Lower Unit (Counter Rotation Model) - Yamaha 250GETO Service Manual

LOWR
2. Calculate the reverse gear shim thick-
ness (T2) as shown in the examples
below.
NOTE:
"R" is the deviation of the lower case dimen-
sion from standard, and "A" is the deviation of
the propeller shaft housing 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 propeller 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 backlash when
the unit is assembled.
Calculation formula:
Reverse gear shim thickness (T2) =
21.00 – R/100 – A/100 – M2
Example:
If "M2" is 19.92 mm and "R" is (– 1) and "A" is
(– 3), then
T2 = 21.00 – (– 1)/100 – (– 3)/100
– 19.92 mm
= 21.00 + 0.01 + 0.03 – 19.92 mm
= 1.10 mm
6-27
Lower unit
If "M2" is 19.92 mm and "R" is (+ 3) and "A" is
(– 5), then
T2 = 21.00 – (+ 3)/100 – (– 5)/100
– 19.92 mm
= 21.00 – 0.03 + 0.05 – 19.92 mm
= 1.16 mm
3. Select the reverse gear shim(s) (T2) as
follows.
Calculated numeral
at 1/100th place
1, 2
3, 4, 5
6, 7, 8
9, 10
Available shim thicknesses:
0.10, 0.12, 0.15, 0.18, 0.30, 0.40 and
0.50 mm
Example:
If "T2" is 1.10 mm, then the reverse gear shim
is 1.08 mm.
If "T2" is 1.16 mm, then the reverse gear shim
is 1.15 mm.
Backlash
(regular rotation model)
Measuring the forward and reverse
gear backlash
1. Remove the water pump assembly.
2. Set the gear shift to the neutral position
at the lower unit.
Shift rod push arm:
90890-06052
Rounded numeral
0
2
5
8
69D60035
6S35H11