Piper COMANCHE PA-24-180 Service Manual page 427

PIPER COMANCHE SERVICE MANUAL
e.
If it wu possible to eleericallv disconneer the starter from the starter solenoid, the startng
nbrator may be energized by turning the starter switch on.
f.
If starer wu not electrically removed from stater solenoid, it is necessary o connect a jumper
lead from rsarter swich terminal on vibrator to ungrounded terminal on battery. This will energize the
srting vibrator.
c.
Holding the number one cylinder spark plug Lead approximately 3/16 to 1/4 inch away from a
good ground, a series of hot sparks should occur.
CAUTION
Grasp the spark plug lead far enough away from the connection so u
not to produce any dangerous electrcal shock.
h. If the spark does not jump the gap, check the applied voltage to bte strng
vibrator. This voluge
sho
be either 12 or 24 volts depending upon the system being checked.
i.
If voltage is correct, check the contact pount of the magneto. Both sets of contact points shall be
opened.
j.
Rejec all units not complying with the preceding requirements or which show any vsual defects.
7B-8. Spark Plugs.
78B-9. Removal Of Spark Plugp.
a.
Loosen the coupling nut on the harness lead and remove the terminal insulator from the spark plug
barrel well.
NOTE
When withdrawing
the igniion cable lead connecton
from the plug.
care must be taken to pull the lead straighr out and in line with the
center line of the plug barrel; otherwise, a side load will be applied
which
frequently results in damage
to the barrel insulator and
connector.
If the lead cannot be removed easly in this manner, the
resisung contact between the neoprene collar and the barrel insulator
will be broken by a rotary twistng of the collar. Avoid undue discortion
of the collar and possible side loading of the barrel insulator.
b.
Remove the spark plug from the engine. In the course of engine operation
carbon and other
combusuon products will be deposited on the end of the spark plug and will penetrate the lower threads to
some degree. As a result, greater torque is frequently required for removing a plug than for its installation.
Accordingly, the torque limiaions
given do not apply to plug removal and sufficient torque must be used
to unscrew the plug. The higher torque in removal is not as detrimental as in installaton. since it
cannot
stretch the tnreaded
section. It does. however, impose a shearing load on this section and may, if
sufficiently severe, produce a failure in this location.
POWER PLANT
ISSUED: 8/18/72
2 F21