8-36. INSTALLATION OF HARNESS. Before installing harness on magneto, check mating surfaces for
cleanliness.
a. Place the harness terminal plate on the magneto and tighten nuts around the plate alternately to seat cover
squarely on magneto. Torque nuts from 18 to 22 inch pounds.
b. Route ignition wires to their respective cylinders.
c. Clamp the harness assembly in position and replace the engine baffle plate.
d. Connect the leads to the spark plugs.
8-37. SPARK PLUGS.
8-38. REMOVAL OF SPARK PLUGS. (Refer to Figure 8-27.)
a. Loosen the coupling nut on the harness lead and remove the terminal insulator from the spark plug barrel
well.
—NOTE—
When withdrawing the ignition cable lead connection from the plug,
care must be taken to pull the lead straight 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
c o n n e c t o r. If the lead cannot be removed easily in this manner, the
resisting contact between the neoprene collar and the barrel insulator
will be broken by a rotary twisting of the collar. Avoid undue distortion
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 combustion
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
limitations 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 installation, since it cannot stretch the threaded section. It
does, however, impose a shearing load on this section and may, if sufficiently severe, produce a failure in this
location.
—NOTE—
Torque indicating handle should not be used for spark plug removal
because of the greater torque requirement.
c. Place spark plugs in a holder that will identify their position in the engine as soon as they are removed .
—NOTE—
Spark plugs should not be used if they have been dropped.
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
POWER PLANT
1K10
