Holley MCarbHoll2110 1957 Carburetor manual
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3. MAJOR SUBASSEMBLIES
Carburetor Model 2110 Series is composed
of three major subassemblies: the air horn as
sembly, the main body assembly, and the throttle
body assembly. The air horn contains the choke
mechanism, the balance tube for venting the float
chamber to the carburetor air inlet, and the float
assembly which actuates the fuel inlet valve. The
die cast main body contains the float chamber, the
accelerating pump, the diaphragm type power
valve, and the removable fuel metering parts, such
as the main jets, idle tubes, and booster venturi
nozzle bars. The cast iron throttle body contains
the throttle plates and the idle speed and mixture
adjusting screws. Carburetors used with auto
matic transmission engines have a bracket
fastened under the air horn screws on which to
mount the dashpot assembly. Model 2110-EE and
2110-FF Carburetors have a choke bracket or a
throttle control bracket. Carburetor Model
2110-EEC has an automatic choke which is an
integral part of the carburetor. Model 2110-G
has a built in Centri-Vac governor.
OPERATION
To meet the requirements of modern auto
motive engines, the carburetor must supply the
proper fuel-air mixture during all phases of
operation. The Holley Carburetor Model 2110
Series, to provide the correct mixture, is equipped
with four basic metering systems. They are the
idle system, the accelerating pump system, the
main metering system, and the power enrichment
system. These four systems are individually
calibrated to deliver an economical mixture for
normal cruising conditions; a richer mixture when
high power output is desired, and a still richer
mixture for smooth idle and low speed perform
ance, also the accelerating pump provides fuel
for instant acceleration.
In addition, there is a fuel inlet system, which
provides the four basic metering systems with a
constant supply of fuel, and also a choke which
provides a means of temporarily enriching the
mixture to aid in starting and running a cold engine.
When the engine is running, differences in air
pressure within the carburetor provide the proper
discharge of fuel for the various engine speed and
load conditions, as explained in the following
paragraphs. In the explanation of the basic fuel
metering systems, the air in the carburetor float
chamber will be considered as being at normal
atmospheric pressure. It may actually be at a
pressure very slightly less than atmospheric, due
to the restriction of the air flow through the air
cleaner. However, to simplify the explanation of
the function of the fuel metering systems, this
factor will be disregarded and the pressure will
be considered as being atmospheric.
1.
FUEL INLET SYSTEM
All of the fuel, for the four basic metering
systems, enters the carburetor through the fuel
inlet valve. This valve is frequently referred to
as the fuel inlet needle and seat assembly. The
amount of fuel entering the carburetor is deter
mined by the amount of space between the tip of
the needle and its seat. Movement of the needle
in relation to the seat is controlled by the float
and lever assembly.
Movement of the float and
lever assembly is in turn regulated by fluctuations
in the fuel level. Even a slight drop in the fuel
level causes the lowering of the float to open the
needle valve, allowing more fuel to enter the float
chamber.
When the fuel in the float chamber
reaches a specified level, the needle valve is
forced upward by action of the float thus restricting
FUEL INLET SYSTEM
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