Piper Comanche PA-24 Service Manual page 551

PIPER COMANCHE SERVICE MANUAL
e. If it was possible to eleetrically discoMect the
starter
from the starter solenoid, the starting
vibracor may be merpzed by turning the starter switcb on.
f. If starter was not electrically removed from starter solenoid, it is necessary to ~OD.D.ect
&
jumper
lead from starter switcb ,ermin&l on vibrator
'0
ungrounded termi.aal OD battery. Tbis will enerpze the
Hartinl vibrator.
c. Holding the number one cylinder spark plug lead .pproximately 3/16 to 1/4 incb .way from.
good ground, • seri .. of hot sparks should occur.
sho
I.
CAUTION
Grup the spark plug lead far enough .way from the coMection so as
Dot to produce &Dy
dangerous
eleetrical shock.
If 'he spark does not jump the gap, cbeck the applied voltage '0 the starting vibrator. This voltage
Dc .ithor 12 or 24 vola ckpcnding upon 'he system being checked.
If voltage is correct, check thc contact poinu of thc magncto. 80th sea of contact p"ina shall be
opcned.
j. Reject all unia not complying with the preceding requirements or which show Uly visual defccu.
7848. Spark Plugs.
7849. Removal Of
S ..... k
Plugs.
a. Loosen the coupling nut on the harness lead and remove the terminal Jnsuator from the spark plug
barrel well.
NOTE
When withdraWing the ignition cable lead connection from the plug.
cue must be taken to pull the lead stn.ight out and in line with the
center line of the plug barre" otherwise, • side load
will
be .pplied
which. frequently results in damage to the barrel insulator and
connector. If the lead c:annot be removed easily in this manner. the
resisting contact between the neoprene coUar and the barrel insulator
will
be broken by a rotuy tw}5cng of the coUat. AVOid undue distortion
of the collat and possible side loading of the banei insulator.
b. Remove the spark plug from the engine. In the course of engine operation. carbon
~nd
other
combustion pro-jucts wtll
be deposited on the end of the spark plug iIlld
will penc.tn.te the lower thre3.ds
to
some degree. As ~ result. greater torque is frequendy required for removmg a plug than for Its inst.illanon.
Accordingly. the torque limJutions 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 mstillation. Since it cannot
stretch the threaded section. It
d~.
howc:ve:-, impose a shewg load on thiS section and may. If
sufficiently severe, produce a failure in chis locanon.
POWER PLANT
ISSUED: 8/18172
2 F21