ELECTRIC STARTER5-47EAS24790CHECKING THE STARTER MOTOR1. Check:• CommutatorDirt → Clean with 600 grit sandpaper.2. Measure:• Commutator diameter “a”Out of specification → Replace thestarter motor.3. Measure:• Mica undercut “a”Out of specification → Scrape the mica tothe proper measurement with a hacksawblade that has been grounded to fit thecommutator.TIPThe mica of the commutator must be undercutto ensure proper operation of the commutator.4. Measure:• Armature assembly resistances (commu-tator and insulation)Out of specification → Replace thestarter motor.▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼a. Measure the armature assembly resis-tances with the digital circuit tester.b. If any resistance is out of specification,replace the starter motor.▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲5. Measure:• Brush length “a”Out of specification → Replace the brushholder.Limit23.5 mm (0.93 in)Mica undercut (depth)1.50 mm (0.06 in)Digital circuit tester90890-03174Model 88 Multimeter withtachometerYU-A1927Armature coilCommutator resistance0.0090–0.0110 Ω at 20 °C (68°F)Insulation resistanceAbove 1 MΩ at 20 °C (68 °F)1. Commutator resistance2. Insulation resistanceLimit7.19 mm (0.28 in)
