Mercury Optimax 115 Service Manual page 391

7. 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) or on line marked "4" if gear ratio is
2.3:1 (13 teeth on pinion gear).
a -
b -
c -
d -
e -
8. Lightly turn driveshaft back-and-forth (no movement should be noticed at propeller
shaft).
9. Dial indicator registers amount of backlash which must be 0.018 in. to 0.027 in. (0.46
mm to 0.69 mm) for the 1.87:1 gear ratio, 0.015 in. to 0.022 in. (0.38 mm to 0.56 mm)
for the 2:1 gear ratio and 0.018 in. to 0.023 in. (0.46 mm to 0.58 mm) for the 2.3:1 gear
ratio.
10. If backlash is LESS than the specified minimum, REMOVE shim(s) from in front of for-
ward gear bearing race to obtain correct backlash. When reinstalling pinion nut, apply
Loctite 271 on threads of nut.
11. If backlash is MORE than the specified MAXIMUM, add shim(s) in front of forward
gear bearing race to obtain correct backlash. When reinstalling pinion nut, apply Loc-
tite 271 on threads of nut.
NOTE: By adding or subtracting 0.001 in. (0.025 mm) shim, the backlash will change ap-
proximately 0.001 in. (0.025 mm ).
REVERSE GEAR
Determining Reverse Gear Backlash
Although reverse gear backlash is not adjustable, it may be checked as follows:
1. Propeller shaft and bearing carrier must be completely assembled and installed in
gearcase.
2. Install shift shaft in gearcase.
3. Shift gearcase into reverse.
4. Slide 6 in. x 1.5 in. I.D. (152.5 mm x 38.0 mm) piece of PVC pipe over propeller shaft
and position pipe against bearing carrier.
90-855347R1 JANUARY 1999
d
e
a
b
Thread Stud Adaptor (from 91-14311A1)
Stud
Backlash Indicator Tool (91-78473)
Dial Indicator Holder (91-89897)
Dial Indicator (91-58222A1)
RIGHT HAND NON-RATCHETING
c
51880
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