TOHATSU BFT250A Service Manual page 545

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REVERSE BEVEL GEAR BACKLASH
Backlash adjustment must be made after adjustment of
each gear shim (page 17-34).
Install the following parts except the water pump.
– Vertical shaft/forward bevel gear (page 17-28)
– Propeller shaft holder (page 17-17)
– Shift rod (page 17-15)
Wrap a shop towel [1] around the shift rod spline [2],
and use pliers to turn the shift rod in the direction shown
(cutout of the shift rod spline [3] is toward the left side of
the cruising direction [4]).
Set the special tools as shown.
TOOLS:
Backlash indicator tool [5]
Backlash inspection tool set
• Adjust the dial indicator [6] so its needle is at the line
of the indicator clip [7].
• Align the backlash indicator tool with line of the base
plate [8]
Turn the vertical shaft lightly right and left and record
the dial indicator reading.
Measure the backlash at six lines of the base plate.
Turn the vertical shaft 180° and measure the backlash
in the same manner.
When measuring the backlash, do not turn the propeller
shaft by turning the vertical shaft.
Obtain the reverse bevel gear backlash using the dial
indicator runout and the following formula.
Formula:
Backlash = Dial gauge runout ÷ 0.806
Example:
When dial gauge runout is 0.285 mm (0.0112 in),
Backlash =
0.285 mm (0.0112 in) ÷ 0.806 = 0.35 mm (0.014 in)
STANDARD VALUE:
0.41 – 0.64 mm (0.016 – 0.025 in)
If the backlash is too large compared to the standard
value, increase the reverse bevel gear shim thickness
and recheck the backlash.
If the backlash is too small compared to the standard
value, reduce the reverse bevel gear shim thickness
and recheck the backlash.
• Use the special tool when reverse bevel gear/
bearing is removed to adjust the backlash again.
Install the water pump (page 11-12).
After installation, inspect the gear case pressure (page
17-42).
GEAR CASE (COUNTER ROTATION)
07SPJ-ZW0030B
070PJ-ZX20200
[1] [2]
[4]
[3]
Viewed from the upper side:
[6]
[8]
[7]
[5]
17-41