Yamaha F25A - Page 262

6-29
E
LOWR
SHIMMING (EXCEPT FOR USA AND CANADA)
1. Measure:
● Measurement (M)
NOTE:
Place the propeller shaft housing in the
recess of the shimming plate.
Shimming plate 1:
90890-06701
Digital caliper:
90890-06704
2. Calculate:
● Reverse gear shim thickness
NOTE:
● “R” is the deviation of the lower case
dimension from standard. It is stamped
on the anode mounting surface of the
lower case in 0.01 mm units. If the “R”
mark is missing or unreadable, assume an
“R” value of “0”, and check the backlash
when the unit is assembled.
● If the “R” mark is negative (–), then sub-
tract the “R” value from the measure-
ment.
Example:
If M is “78.79 mm” and “R” is “+5” then:
T2 = 80 + (+5)/100 – 78.79 mm
= 80 mm + 0.05 – 78.79 mm
= 1.26 mm (0.050 in)
If M is “78.75 mm” and “R” is “–3” then:
T2 = 80 + (–3)/100 – 78.75 mm
= 80 – 0.03 – 78.75 mm
= 1.22 mm (0.048 in)
Reverse gear shim thickness (T2) =
80 mm + R/100 – M