TOHATSU BFT75A Service Manual page 471

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GEAR CASE
Attach the special tool to the vertical shaft [1] as shown,
and adjust the dial gauge [2] so its needle is at line "1"
of the special tool (backlash indicator tool).
TOOL:
Backlash indicator tool [3]
Backlash indicator attachment [4] 07SPK-ZW10100
Turn the vertical shaft lightly right and left and record
the dial indicator reading.
Measure the backlash at four points (by turning the
vertical shaft in increments of 90°) in the same manner.
Do not turn the propeller shaft when turning the vertical
shaft.
Obtain the forward bevel gear backlash using the dial
gauge runout and the following formula.
Formula:
Backlash = Dial gauge runout x 0.80
Example:
When dial gauge runout is 0.30 mm (0.012 in),
Backlash =
0.30 mm (0.012 in) x 0.80 = 0.24 mm (0.009 in)
STANDARD VALUE:
0.10 – 0.28 mm (0.004 – 0.011 in)
If the backlash is too large, increase the forward bevel
gear shim thickness and recheck the backlash.
If the backlash is too small, reduce the forward bevel
gear shim thickness and recheck the backlash.
• Use special tool when taper bearing (50 x 82 x 21.5
mm) [outer race] is removed to adjust the backlash
again.
Install the water pump (page 11-9).
After water pump installation, inspect the gear case
pressure inspection (page 16-42).
GEAR CASE PRESSURE INSPECTION
• Perform the gear case pressure check and check for
pressure leakage after disassembling and
reassembling the gear case.
• In principle, the pressure check should be made on
the gear case before filling it with gear oil and before
installing it on the outboard motor. However, the
check can be made with the gear case filled with
gear oil.
Remove the oil check bolt [1] and the O-ring [2].
Install the adapter [3] (STV-334Y: commercially
available) in the oil check bolt hole.
Attach the hose end of the pressure tester [4] (STV-
V34: commercially available) to the adapter.
Do not screw in the adapter and the hose end with
force.
16-42
07SPJ-ZW0030B
90°
90°
[3]
[1]
[1]
[4]
90°
90°
[2]
[4]
[2]
[3]