2004 SR Johnson 4 Stroke 9.9-15HP Outboards Service Manual, Page 80Get this manual
IGNITION AND ELECTRICAL STARTER MOTOR
Inspection and Servicing
Inspect: Pinion teeth Replace pinion if damaged or wornCheck: Clutch movement Replace if damaged
Armature and Commutator
Inspect the commutator surfaceIf surface is gummy or dirty, clean with emery paper
Measure: Commutator outside diameter
Vernier calipers Outside diameter: Standard: 30 mm (1.18 in) Service limit: 29 mm (1.14 in)