Piper Navajo Chieftain PA-31-350 Service Manual page 662

NAVAJO CHIEFTAIN SERVICE MANUAL
TABLE XI-V. TROUBLESHOOTING CHART (ELECTRICAL SYSTEM) (cont.)
Trouble
Cause
Remedy
Motor fails to
operate. (cont.)
with the sanded side next
to the brush. Pull sand-
paper in the direction of
rotation, being careful to
keep it in the same contour
as the commutator.
CAUTION
Do not use coarse sandpaper
or emery cloth.
After seating, clean thor-
oughly to remove all sand
and metal particles to
prevent excessive wear.
Keep motor bearing free
from sand or metal
particles.
Dirty commutator.
Shorted, grounded, or
open armature.
Grounded or open
field circuit.
If commutator is rough or
dirty, smooth and polish
with No. 000 sandpaper.
If too rough and pitted,
remove and turn down.
Blow out all particles.
Remove and replace with
an armature known to be
in good condition.
Test and then replace
with new part.
Motor operates at
proper speed but
fails to crank
engine.
Low motor and
cranking speed.
Faulty Bendix drive.
Worn, rough, or im-
properly lubricated
motor or starter.
Remove Bendix drive as-
sembly. Clean and check,
replace.
Disassemble, clean, inspect
and relubricate, replacing
ball bearings if worn.
Revised: 10/5/83
ELECTRICAL SYSTEM
3E12