TM 5-3810-288-12
ent condition. If available, install the plugs in a spark plug
tester and check for adequate performance.
(3) Adjustment. Gap the spark plugs to a clearance
of from 0.023 to 0.028 inch. Use a round feeler gauge in
preference to a flat gauge, since a flat gauge will give
incorrect readings.
(4) Installation. Install spark plugs finger tight. Then
tighten them to 20 foot pounds, using a torque wrench, if
available. If not available, snug the plugs down firmly. Do
not overtighten.
f.
Suppression Leads.
(1) Removal. Refer to figure 3-53 for a view of the
suppression leads. These leads are from the distributor
(ignitor) to the spark plugs. The leads are removed by
unscrewing them at the distributor and the individual spark
plugs.
(2) Test. Connect suppression lead to positive side
of any battery. Place the tip of a light bulb on the negative
terminal. Hold the other end of this lead against the metal
side of the light bulb. If the light bulb illuminates, the lead is
at least not an open circuit, and may be fit for further use. If
the light does not come on, replace the lead. If an ohmmeter
STEP 1.
REMOVE MOUNTING CAP-
is available, the lead should test above 2,000 ohms per inch
SCREWS AND LOCKWASHERS.
of length.
STEP 2.
REMOVE WATER PUMP AND
SHEAVE AS AN ASSEMBLY.
g. Slave Cable Receptacle. Refer to figure 3-55 and
STEP 3.
REINSTALL A LIKE, SERVICE-
replace a faulty save receptacle.
ABLE WATER PUMP.
h. Lights.
ME 3810-288-12/3-49
Figure 3-49. Water pump, removal and
replacement.
faulty headlights.
gap as described in this paragraph. Reinstall the
cover (fig. 3-53).
(2) Marker lights, dome lights, flood fights, and
trouble lights. Each of the various types of lights furnished
Note. Always replace spark plugs, points,
with this machine, both upper and carrier portions, are
and condenser at the same time spark plugs are
illustrated in figure 3- 57. Refer to figure 3-57 and remove or
replaced.
replace any defective light component.
e. Spark Plugs.
i. Reverse Polarity Relay.
(1) Removal. Unscrew the shielded ignition
(1) General. The reverse polarity relay contains a
leads at the top of the spark plugs and place a
solid state rectifier which prevents current from flowing
deep socket spark plug wrench on the spark plug
through the engine starting circuit in the wrong direction.
hexagon. Unscrew spark plugs and remove. Be
Refer to the wiring diagram of the relay in figure 3-58.
careful not to lose the metal gasket beneath the
spark plug.
engine, connect a 24 volt source to connector C (fig. 3-58).
(2) Test. Inspect spark plugs for obvious
Then touch the relay case to ground.
cracks, broken or severely worn points, pitting,
discoloration, or accumulations of foreign ma- 3-57
terial. Discard any spark plug not in good appar-
