The carburetor is of the down-draft type and is
equipped with fixed jets which cover all speed ranges except the idle
range, which is controlled by two adjusting needles. The carburetor is
equipped with adjustable accelerating pump and a fast idle device for
the prevention of stalling while operating below normal temperature.
The idle needle valve controls a fuel mixture for
closed throttle operation. Turning the adjustment screw clockwise gives
a leaner mixture and counter clockwise a richer mixture. (A vacuum gauge
is desirable when adjusting idle needle valves to obtain the highest
The carburetor float level may be checked by removing
the inspection screw plug in the side of the body. The fuel level should
be even with the bottom of inspection hole with the engine idling. Two
positions are provided on the accelerator pump lever in order to give a
greater or lesser discharge of fuel, depending upon climatic conditions.
For warm weather or for high altitudes above 3,000
feet the pump link should be in the hole in the accelerating pump lever
which is nearest to the throttle shaft. For cold weather operation, the
pump link should be in the pump lever hole which is farthest from the
CARBURETOR AIR CLEANER
The heavy duty oil bath air cleaner mounted on the
carburetor is a protection against dirt, dust and abrasives entering the
engine through the carburetor. The air cleaner should be cleaned and
re-oiled at least twice a year.
An automatic choke controls the mixture of gasoline
and air at the carburetor according to the temperature of the engine,
and operates when starting and during the time the engine is reaching
operating temperature. After the engine is warm (due to the heat of the
exhaust manifold affecting the choke) the choke valve opens and stays in
this open, or "off" position until the manifold cools.
The automatic choke and its linkage, both at the
choke and the valve in carburetor air horn, should under NO
CIRCUMSTANCES BE OILED OR LUBRICATED. All of the moving parts should be
dry and free. Oil will cause sticking and unsatisfactory engine
performance. Dirt, oil or anything that retards the free action of the
linkage (particularly the choke valve pivot pins in the carburetor air
horn) should be washed off with a gum solvent. This is particularly
important during cold weather.
AUTOMATIC CHOKE ADJUSTMENT
Open throttle one-fourth way.
Remove air cleaner from carburetor and cover from
Line up the hole in the armature and the hole in
the magnet core, and clamp in this position.
Loosen clamp screw on automatic choke lever and
move the lever down until carburetor choke valve is tight. There
should be no play in the choke valve.
- Hold lever in this position, tighten clamp screw and replace
automatic choke cover.
GASOLINE GAUGE AND TANK
The gasoline gauge is of the plain float type,
protected by a wire screen located in the top center of the gasoline
tank protruding through the engine hood. The capacity of the gasoline
tank is 18 gallons.