Mazda MX-5 Miata / Grand Touring. Manual — part 172

Fig. 11: Inspecting Continuity Between Commutator & Core
Courtesy of MAZDA MOTORS CORP.

2. Verify that there is no continuity between the commutator and the shaft using a tester.



If there is continuity, replace the armature.

2008 Mazda MX-5 Miata Grand Touring

2008 ENGINE Starting System - MX-5 Miata

Fig. 12: Inspecting Continuity Between Commutator & Shaft
Courtesy of MAZDA MOTORS CORP.

3. Place the armature on V-blocks, and measure the runout using a dial indicator.

Starter armature runout

0.1 mm {0.004 in} max.

2008 Mazda MX-5 Miata Grand Touring

2008 ENGINE Starting System - MX-5 Miata

Fig. 13: Measuring Armature Runout Using Dial Indicator
Courtesy of MAZDA MOTORS CORP.

4. Measure the commutator diameter.



If not within the minimum specification, replace the armature.

Starter commutator diameter

Standard: 29.4 mm {1.16 in}

Minimum: 28.8 mm {1.13 in}

2008 Mazda MX-5 Miata Grand Touring

2008 ENGINE Starting System - MX-5 Miata

Fig. 14: Measuring Commutator Diameter
Courtesy of MAZDA MOTORS CORP.

5. Measure the segment groove depth of the commutator.



If not within the minimum specification, undercut the grooves to the standard depth.

Segment groove depth of starter commutator

Standard: 0.5 mm {0.02 in}

Minimum: 0.2 mm {0.008 in}

2008 Mazda MX-5 Miata Grand Touring

2008 ENGINE Starting System - MX-5 Miata