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CHECKING THE STARTER MOTOR

1. Check:
    • Commutator

       If dirty -> Clean with 600 grit sandpaper.

2. Measure:
    • Mica undercut "a"

      If out of specification -> Scrape the mica to the proper measurement with a hacksaw blade that has been
      grounded to fit the commutator.
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Mica undercut (depth)
    0.70 mm (0.03 in)
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The mica of the commutator must be undercut to ensure proper operation of the commutator.
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3. Measure:
    • Armature assembly resistances (commutator and insulation)

      If out of specification -> Replace the starter motor.

      a. Measure the armature assembly resistances with the pocket tester.
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Digital circuit tester
    90890-03174

Model 88 Multimeter with tachometer
    YU-A1927
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Armature coil
    Commutator resistance "1"

    Continuity (0.0050-0.0150 ohms. at 20 °C (68 °F))

    Insulation resistance "2"

    No continuity (Above 1 Mohms at 20 °C (68 °F))
      b. If any resistance is out of specification, replace the starter motor.
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4. Measure:
    • Brush length "a"

      If out of specification -> Replace the brush set assembly.
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Brush overall length
    12.0 mm (0.47 in)

Limit
    6.50 mm (0.26 in)
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5. Measure:
    Brush spring force

    If out of specification -> Replace the brush set assembly.
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Brush spring force
6.025-6.515 N (614-664 gf, 21.69-23.45 oz)
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6. Check:
    • Gear teeth

       If Damaged/Worn -> Replace the starter motor.

7. Check:
    • Bearing

      If Damaged/Worn -> Replace the starter motor.

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