General Methods to Attain Proper Suppression
(2) Loosen the nut (1) that holds each ignition
Essentially, suppression is attained by providing a
lead to the magneto (3); remove the
shielded ignition leads.
currents. The methods used to attain suppression
(3) Position the ends of the new leads on the
include shielding the ignition and high-frequency wires,
spark plugs and on magneto; tighten nuts
and grounding the frame with bonding straps.
to secure leads.
Replacement of Suppression Components
b. Ground Strap.
(1) Remove the nuts (5) that secure the
a. Shielded Ignition Leads.
ground strap (6) to the magneto (3) and to
(1) Loosen the nut that holds one end of each
the engine gear cover; remove the ground
ignition lead (2) to the spark plug;
disconnect the leads from the spark plugs.
(2) Position the new ground strap on the
magneto and on the engine gear cover;
secure with two nuts.
Section V. FUEL SYSTEM
57. Description and Function
a. General. The purpose of the fuel system is to
store, convey, mix fuel with air, and then vaporize and
introduce the mixture into the engine. Fuel is stored in
the gasoline tank. It is filtered and flows through the fuel
supply lines to the carburetor under the pressure of a
fuel pump. The carburetor mixes the fuel with the
proper proportions of air and at the same time breaks it
into very fine spray particles. This atomized spray
changes to vapor as it travels through the heated intake
b. Fuel Pump. The mechanical fuel pump (4, fig.
2) is used to pump fuel from the fuel tank to the
carburetor. The fuel pump mounts on the cylinder block
and is driven by an eccentric cam on the engine
camshaft contacting the fuel pump rocker arm.
Constant fuel pressure is maintained by an air dome and
a pulsating diaphragm operated and controlled by
linkage which adjusts itself to pressure demands.
c. Carburetor. The carburetor (3, fig. 2) is an
updraft carburetor of the double venturi design. Two
body castings are used. The fuel bowl hugs the center
line of the carburetor and together with the duplex float
makes it possible for this unit to maintain proper
metering of the air and fuel to the engine, without
Figure 17. Fuel pump installation.
flooding, when the vehicle is operated on extreme:
angles. It is a sealed and balanced carburetor in that all
d. Air Cleaner. All engines, when operating,
air for bowl chamber ventilation and idling must come
consume several thousand cubic feet of air per hour.
through the air cleaner.
Two venturis aid in the
Since dusty air is full of abrasive matters the engine will
complete vaporization of fuel. The power jet and
soon wear excessively if the air cleaner (2, fig. 4) does
accelerating pump systems operated by engine vacuum
not remove the dust before entering the cylinders.
are completely enclosed and protected from dirt.
Operating conditions determine the air cleaner