Forward Gear Backlash - Mercury 225 EFI Service Manual

LEFT HAND NON-RATCHETING

Forward Gear Backlash

CHECKING
NOTE: If the bearing preload tool has not already been set up, see "Drive Shaft - Bearing
Preload Tool", 'Installation' section first.
1. Install a dial indicator as shown in the following figure.
a -
b -
c -
d -
e -
2. Align the dial indicator pointer so that it is perpendicular to and touching the "I" mark
on the dial indicator tool. Tighten the indicator tool onto the drive shaft and rotate the
drive shaft so that the needle in the dial makes at least one full revolution and comes
to "0" on the dial indicator scale.
3. Take the backlash readings by lightly turning the drive shaft back and forth.
a. Observe the dial indicator and record the reading.
b. Loosen the indicator tool and rotate the drive shaft 90 degrees in a clockwise di-
c. Repeat step 4 above and take and record another reading. Repeat step 4 until a
4. Add the four readings together and divide the sum by 4. This is your average backlash,
which should be 0.017 in. - 0.028 in. (0.431mm - 0.711mm) (for 1.75:1 and 1.87:1 ra-
tios).
5. If backlash is MORE than the specified MAXIMUM, REMOVE shim(s) from in front of
forward gear bearing race to obtain correct backlash. When reinstalling pinion nut, ap-
ply Loctite 271 to threads of nut.
6. If backlash is LESS than the specified MINIMUM, add shim(s) in front of forward gear
bearing race to obtain correct backlash. When reinstalling pinion nut, apply Loctite
271 to threads of nut.
Page 6B-78
a
c
b
a
Nuts (4) (Obtain Locally)
Threaded Rod [3/8 in. (9.5mm) obtain locally]
Dial Indicator Holding Tool (91-83155)
Dial Indicator (91-58222A1)
Indicator Pointer
f - Backlash Indicator Rod (91-53459) (for 1.75:1)
Backlash Indicator Rod (91-78473) (for 1.87:1 ratio)
rection.
total of 4 backlash readings have been taken.
f
e
d
90-884294 OCTOBER 2001
57939