TM 55-2840-241-23
c. Installation.
(1) Install serviceable exciter on the engine and
secure with three nuts (4) and washers (5). Tighten
nuts (4) to 30-40 in. lb.
(2) Attach igniter lead (18) to the exciter.
Tighten coupling nut to 50-70 in. lb.
(3) Attach power input lead to the exciter input
terminal. Secure with washer (2) and nut (1). Tighten
nut to 8-12 in. lb.
5-36. Spark Igniter
a. Removal.
To prevent personnel injury due to elec-
trical shock ensure ignition system has
been off for at least five minutes before
removing igniter to dissipate all energy
stored in condenser. Ground igniter lead
to engine using an insulated screwdriver.
(1) Disconnect igniter lead (18, figure 5-16) at
igniter (19). Prevent lead from twisting while remov-
ing nut.
(2) Separate lead from igniter by pulling
straight out without any rotational motion.
(3) Remove lock wire and unscrew igniter (19).
The igniter connector well must be kept
dry and free from foreign material.
Damage to igniter and igniter load could
result.
b. Cleaning.
(1) Clean igniter connector well with a clean
dry cloth. Do not wash with solvent.
Under no circumstances, wire brush,
sand blast, vapor blast, or scrape the igni-
ter. Any of these cleaning methods can
damage the semi-conductor.
(2) Normal soot or carbon formation on the tip
is not detrimental to igniter operation and need not be
removed. If cleaning is desired, wipe the metal tip with
a soft dry cloth.
(3) Remove any sizable carbon deposits with a
blunt non-metallic instrument. Be careful not to
damage the semi-conductor material.
c. Inspection.
(1) Inspect center electrode; replace igniter if
electrode is loose (See figure 5-17.)
(2) Inspect ceramic for cracks; if any cracks are
visible through carbon coating, replace ignite.
4364A
Figure 5-17. Spark Igniter
d. Testing.
(1) With a good exciter and igniter lead, check
igniter operation before installing in engine.
(2) Apply 28 volts dc to the exciter; observe the
rate of firing. Normal operation is six sparks per second
minimum.
(3) Replace igniter if it fails to fire or fires inter-
mittently.
e. Installation.
(1) Apply a light coat of antiseize compound
(item 26, table 2-2) to the threads and install serviced
or new igniter; tighten to 150-200 in. lb. and lockwire
(item 10, table 2-2) to fuel nozzle.
(2) Connect igniter lead; tighten to 70-90 in. lb.
5-37. Spark Igniter Lead.
a. Removal.
To prevent personnel injury due to elec-
trical shock ensure ignition system has
been off for at least five minutes before
disconnecting igniter lead. Ground lead
to engine using an insulated screwdriver.
(1) Remove the lead (18, figure 5-16) from the
ignition exciter (3) and the spark igniter (19).
Change 23
5-27
