Yanmar 4TNV98 Service Manual page 230

Figure 11-13
See Starter Motor Specifications on page 222 for
the service limit.
Measure Commutator Insulation Depth
Measure the depth of the insulating material
(Figure11-14, (1)) between commutator segments
(Figure11-14, (2)). If the depth measures less than
the limit, use a hacksaw blade (Figure11-14, (3)) to
remove the insulating material until the depth is
within the limit.
A normal commutator condition is indicated in
(Figure11-14, (4)). An abnormal commutator
condition is indicated in (Figure11-14, (5)).
Figure 11-14
See Starter Motor Specifications on page 222 for
the service limit.
4TNV98 & 4TNE98 Diesel Engine
Armature Coil Continuity Test
Check for continuity between the commutator
segments using a multimeter (Figure 11-15). The
multimeter should indicate continuity.
If the multimeter does not indicate continuity,
replace the armature.
Armature Coil Insulation Test
Check for continuity between a commutator
segment and the shaft or armature using a
multimeter (Figure11-16). The multimeter should
not indicate continuity.
If the multimeter indicates continuity, replace the
armature.
228
Figure 11-15
Figure 11-16
Section 7. Starter Motor