TM 5-4320-218-15
(2) Unscrew the nut (5) that secures the
shrouds and cooling fins for causes of
ignition switch assembly (7) to the
engine overheating. A rusty brown
f rent panel (2); remove the switch
or grayish-white powdery deposit,
when unleaded or regular gasolines
tag (6) from the switch and pull the
switch assembly out through the rear
have been used, or a white powdery
of the front panel.
deposit, when highly leaded gasolines
have been used is normal. Clean away
b. Cleaning and inspection.
from the electrodes, and use a wire
(1) Clean the parts with a cloth dampen-
brush to clean the threads.
ed with cleaning solvent.
( 3 ) Examine the spark plug electrodes for
(2) Inspect the hardware and switch for
pitting. Replace a badly pitted spark
bad threads; replace a damaged switch
plug; use a file to repair slightly pit-
or any defective hardware.
ted electrodes.
c. Installation.
( 4 ) Set the gap of the spark plugs to 0.030
inch by bending the side electrodes.
(1) Position the switch assembly (7) on
c. Installation. Remove the temporary plugs
the rear of the front panel (2) so
from the spark plug holes, slip a gasket over
that the threaded portion of the switch
each spark plug, and install the spark plug.
extends through the front panel.
Tighten the plugs to 25-30 foot-pounds torque.
(2) Slip the tag (6) over the extended
Connect the loom assemblies to the plugs.
threaded neck of the switch assembly,
and secure the switch with the nut
69. Ignition Switch
(5).
a. Removal (fig. 21).
(3) Connect the ignition switch wire to
(1) Disconnect the ignition switch wire at
the magneto.
the magneto.
Section X. ENGINE COOLING SYSTEM
(4) The lockwasher (11) has two of its
70. Description
tines bent over the nut (12). Position
A combination fan and flywheel forces a
a screwdriver against the tines, and
flow of air through the flywheel shroud to cir-
d r i v e them back, Remove the nut
culate around the cylinders and cylinder heads.
from the crankshaft (23).
Air shrouds are provided to direct the flow of
(5) Hit the end of the crankshaft with a
air.
soft hammer to loosen the flywheel.
Caution: Never operate the engine with any
If the flywheel is not loosened after
part of the shrouding removed. To do so will
two or three blows, use a puller to re-
cause engine to overheat and be damaged.
move it.
(6) Remove the key (24) from the crank-
71. Engine Fan (Flywheel)
shaft.
a. Removal.
b. Cleaning and inspection.
(1) Remove the eight screws (5, fig. 22)
(1) Wash all parts in an approved clean-
and lockwashers (4) that secure the
ing solvent; dry thoroughly. Use a
flywheel screen (15) to the flywheel
wire brush if necessary to clean the
s h r o u d (7); remove the flywheel
rust and scale from the flywheel.
screen,
(2) Inspect the flywheel for cracked or
(2) Examine the hole in the end of the
broken vanes. Replace a damaged fly-
crankshaft for a crank pin setscrew.
wheel,
Remove the setscrew if one is present,
(3) Replace any unserviceable hardware.
c. Installation. Reverse the procedures out-
(3) Drive the crank pin (22) out of the
lined in a above.
crankshaft,
