Piper Navajo PA-31 Service Manual page 777

PIPER NAVAJO SERVICE MANUAL
I
FABLE X1-1. TROUBLESHOOTING
CHART (ELECTRICAL
SYSTEM) (cont.)
Trouble
Cause
Remedy
Motor fails to operate
(cont.).
Shorted, grounded, or
open armature.
Remove and replace
with an armature
known
to be in good condition.
Grounded or open field
circuit.
Test and then replace
with new part.
Motor operates at pro-
per speed but fails to
crank engine.
Low motor and cranking
speed.
Faulty Bendix drive.
Worn, rough, or impro-
perly lubricated
motor
or starter
gearing.
Remove Bendix drive
assembly. Clean and
check, replace.
Disassemble, clean, in-
spect and relubricate,
replacing ball bearings
if worn.
Same electrical
causes
listed under "Motor
fails to operate."
Same remedies
listed
for these troubles.
Excessive arcing of
motor brushes.
Binding, worn,
or im-
properly seated brush
or brushes,
with ex-
cessive side play.
See information above
dealing with this
trouble.
Dirty, rough, pit-
ted or scored
commutator.
Grounded or open field
circuit.
Clean as outlined
above.
Test and replace defec-
tive parts.
Excessive wear and
arcing of motor
brushes.
Rough or scored com-
mutator.
Remove and turn com-
mutator down on a
lathe.
Revised: 10/12/83 ELECTRICAL SYSTEM
4E3