TM 9-2320-266-34
CHAPTER 23
LITTER COMPARTMENT HEATER (AMBULANCE)
(5) Install the cap, and tighten the attaching screws
23-1. General.
to 21 inch-pounds.
The Iitter compartment heater is a self contained, gasoline
(6) Set the spark plug gap (b, below).
burning unit that works independently of the vehicle's engine.
(7) Reinstall the burner assembly in the heater.
23-2. Burner Assembly.
b. Setting Gap. To see the gap, bend the ground
a. Removal and Inspection.
electrode (not the spark plug electrode) until the gap
(1) Disconnect the spark plug cable.
is set at 0.085 inch using tool ST-8933.
23-4. Ignition Coil.
(3) Disconnect the ground wire from the spark plug cap.
a. Removal.
(1) Disconnect the spark plug cable from the coil.
(5) Loosen the burner clamp, and separate the burner
(2) Disconnect the two wires from the coil. Mark
from the beat exchanger. Remove the burner.
them for aid in reassembly.
(6) Inspect the burner for the following conditions:
(3) Remove the attaching nut and washer, and
remove the coil.
(a) The nozzle and inside of the louver plate
and mixer assembly should be coated with a medium layer
Installation.
b.
of black carbon, and the fuel nozzle should have a small
(1) Position the coil on the mounting stud.
gray opening at the orifice.
(2) Install the flat washer and attaching nut.
(b) The outer end of the mixer should be burned
to a gray or reddish color. Some scaling or loose particles
(3) Connect the two wires to the coil.
may be present and should not be considered a defect.
NOTE
Indications of improper operation are an uneven buildup of
black, sooty carbon or an excessively burned or eroded spot
The wire from the ignition unit should be
on the mixer.
attached to the minus (-) terminal.
(c) All air holes in the mixer must be open to
(4) Connect the spark plug cable.
allow the combustion air to mix with the fuel. Also check
Ignition Unit.
23-5.
for evidence of fuel Ieakage around the fuel inlet connector
and between the solenoid coil cup and burner base.
a. Breaker Point Adjustment.
(d) The burner should be replaced as a unit if
(1) Remove the cover from the ignition unit base.
any parts are burned through or damaged.
(2) Rotate the cam until it raises the breaker points'
b. Installation.
contact arm as far as it will go (figure 23-1).
(1) Position the burner assembly on the heat ex-
(3) Rotate the adjusting screw until a gap of 0.018
changer, and tighten the clamp.
inch is obtained between the points.
(4) Rotate the cam 180 and recheck the gap. It
(3) Connect the ground wire to the spark plug cap.
must be between 0.012 inch and 0.021 inch. If it is not,
set the gap at 0.018 inch at this position. Rotate the cam
(4) Connect the red wire to the fuel solenoid coil.
180 and check the gap again. lf it is now between 0.018
(5) Connect the spark plug cable.
inch and 0.021 inch the gap is set. If it still is not within
the proper range, replace the ignition unit (b, below).
23-3. Spark Plug.
(5) Reinstall the cover.
a. Replacement.
The spark plug should not be re-
b. Replacement.
placed unless the ceramic part of the plug is cracked or
chipped. To replace it, use the following procedure:
(1) Remove the cover from the ignition unit base.
(1) Remove the burner assembly from the heater
(2) Disconnect the wires from the ignition unit base.
(3) Remove the attaching screw, and remove the
(2) Remove the cap attaching screws and the cap
ignition unit and gasket.
(3) Remove the spark plug and washers.
(4) Position a new gasket on the ignition unit base,
and position the base on the fuel pump.
(4) Install a new spark plug using new washers.
23-1
Change 2
