Mercury Optimax 115 Service Manual page 445

LEFT HAND NON-RATCHETING
7. Tighten nut to 45 lb. in. (5 Nm). This will seat the forward gear against the forward
thrust bearing and tends to hold the propeller shaft from moving when measuring
backlash.
NOTE: Bearing Preload Tool (91-44307A1) should still be installed from having previous-
ly been used to determine pinion gear depth and reverse gear backlash. If it is not still
installed on gear case, refer to "DETERMINING PINION GEAR DEPTH," previously, for
proper installation procedure.
8. With the proper preload applied to the propeller shaft and the driveshaft, rotate the
driveshaft clockwise 5 to 10 complete revolutions. This will seat the forward gear and
upper driveshaft bearings and thus provide the most accurate backlash readings.
9. If not previously installed:
a. Thread stud adaptor [from bearing preload tool (91-44307A1)] all the way onto
b. Install: Backlash Indicator Tool (91-78473)
10. Position dial indicator pointer on line marked "1" on BACKLASH INDICATOR TOOL,
if gear ratio is 1.87:1 (15 teeth on pinion gear), or on line marked "2" on BACKLASH
INDICATOR TOOL, if gear ratio is 2:1 (14 teeth on pinion gear).
a -
b -
c -
d -
e -
11. Gently rock driveshaft back and forth to determine forward gear backlash.
175 and 200 HP models with 1.87:1 Ratio = 0.018 in. to 0.027 in. (0.46 mm - 0.69 mm)
backlash.
135 and 150 HP models with 2.00:1 Ratio = 0.015 in. to 0.022 in. (0.38 mm - 0.56 mm)
backlash.
Page 6B-44
stud.
Dial Indicator Holder (91-89897)
Dial Indicator (91-58222A1)
e
a
b
Stud Adaptor (from 91-44307A1)
Stud
Backlash Indicator Tool (91-78473)
Dial Indicator Holder (91-89897)
Dial Indicator (91-58222A1)
f - Dial Indicator Pointer
d
f
c
51880
90-855347R1 JANUARY 1999