Piper Navajo PA-31 Service Manual page 510

PIPER NAVAJO SERVICE MANUAL
spark plugs. Torque 360 to 420 inch pounds.
CAUTION
Make certain the deep socket is properly
seated on the
spark plug hexagon as damage to the plug could result
if the wrench is cocked to one side when pressure
is
applied.
b. Carefully insert
the terminal insulator in the spark plug and tighten the
coupling nut.
8-66. STARTING VIBRATOR.
8-67. STARTING VIBRATOR CHECKING PROCEDURE.
a. Disconnect all spark plug leads from the left magneto at the spark plugs.
WARNING
Be sure all left magneto spark plug leads are removed,
thus preventing cross-firing of the magneto and the
possibility of hazardous conditions.
b. Rotate engine crankshaft until number one cylinder
is in its retard firing
position. Using the timing light, check to see that both magneto contact assem-
blies are open.
c. Remove battery terminal from starter switch or remove
starter switch
terminal from vibrator.
WARNING
It is necessary that the starter be electrically removed
from the circuit before the vibrator is put into oper-
ation to eliminate possibility
of starter being energized
during the test.
d. Place left magneto switch in its "ON" position.
e. Connect a jumper lead from starter switch terminal on vibrator to ungrounded
terminal on battery. This will energize the starting vibrator.
f. Holding the number one cylinder spark plug leadapproximately. 187 to. 250
Reissued: 10/12/79
POWER PLANT
2J12