2000-2005 Yamaha F40B Outboard Service Manual, Page 484Get this manual
11=-:1 1STARTER MOTOR
2Check: Commutator undercut Dirtforeign matter -? Clean(with compressed air)
3Measure: Commutator undercut Out of specification -? Replace the armatureCommutator undercut limit 0.8 mm (0.03 in)
4Check: Armature continuity Out of specification -? ReplaceArmature continuity Commutator segments Segment Armature core Segment Armature shaft Continuity No continuity No continuity