Air Cleaner and Piping

bearing supported shaft in the upper part of the

b. Fuel Tank, Lines, and Fittings. The fuel

timing gear cover and is driven off the camshaft

system consists of a fuel tank (fig. 1-1) which is

gear. As the engine speed increases or decreases, the

mounted on the trailer frame beside the engine. It

governor transfers the centrifugal forces to axial

incorporates a 3-way fuel source selector valve (6,

movements which operate the governor control

fig. 2-2) to permit you to select fuel from the fuel

lever. The control lever is connected to the throttle

tank or from an auxiliary source, whichever way

control on the carburetor and as the engine tends to

the valve is operated. A fuel line connects the 3-way

increase, the throttle is closed slightly, resulting in a

valve with the fuel pump.

decrease in engine speed. This decrease in engine

c. Fuel Pump. The diaphragm-type, engine-

speed causes a decrease in centrifugal forces which

driven fuel pump (7, fig. 4-4) is operated by a lobe

causes the governor to operate the control lever in

on the camshaft. It is mounted on the top rear of

the opposite direction. The governor lever then

the engine. Fuel is pumped through a strainer to the

opens the carburetor throttle, tending to speed up

carburetor, w h i c h is mounted on the intake

the engine. In this manner, a balanced condition is

manifold.

reached and the engine speed remains constant, as

d. Fuel Strainer. The fuel strainer (fig. 4-4) is

determined by the throttle control setting. Ad-

mounted between the line from the fuel tank and

justment of the governor is made by changing the

the fuel pump. It is necessary to prevent sediment,

tension of the spring which applies tension to the

dirt, and water from entering the carburetor. In-

governor control lever. Tightening the spring tends

spect the fuel bowl frequently and empty out any

to raise engine speed at any particular throttle

dirt and water; wipe it dry with a clean cloth.

control setting. Decreasing spring tension lowers

e. Carburetor. The side draft-type carburetor (3,

the speed.

fig. 4-7) controls the fuel-air mixture which is fed to

the engine to meet the needs of the engine power

4-17. Air Cleaner and Piping

requirements. A float system controls the level of

NOTE

the fuel in the carburetor float bowl. Adjustment

The air cleaner element must be replaced after one

screws are provided to permit regulation of the

year of service or after it has been cleaned six times,

high-speed operation fuel mixture, the idle mixture,

whichever comes first.

and the idle speed. Choking is controlled manually.

a. Removal and Disassembly.

f. Governor. Engine speed is controlled by the

(1) Remove and disassemble the air cleaner

inter-operation of the governor and carburetor. The

and related parts following the sequence indicated

centrifugal flyball governor rotates on a ball

in figure 4-2.

4-7