Holley MCarbHoll2110 1957 Carburetor manual
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of the carburetor, controls the throttle plates in 
the usual manner. When governing speed is 
reached, a combination of venturi and manifold 
vacuum acts on the governor diaphragm to close 
the throttle plates. Two calibrated by-pass jets 
in the vacuum passages meter the vacuum from 
the venturi and the manifold to provide the correct 
balance for proper operation of the governor. At 
speeds below governing rpm, this vacuum is 
weakened by air bleeding through the governor 
valve so that no premature governing action will 
occur. Filtered air from the carburetor air 
cleaner enters the governor system through the 
governor vent tube. The air flows through an air 
line to the housing enclosing the governor rotor. 
A combination of low pressure from the venturi 
and manifold transmitted through the governor 
system passages, draws the air past the governor 
valve and through another air line to the throttle 
actuating unit on the carburetor. In the controlling 
unit, centrifugal force acting on the rotor, which 
has kept pace with engine speed, overcomes the 
tension of the valve spring and tends to close the 
governor valve when governing speed is reached. 
This greatly restricts the amount of air bleeding 
through to the diaphragm on the carburetor, thus 
allowing the combined venturi and manifold pres
sure differential to operate the diaphragm.
As the pressure differential across the dia
phragm increases, the diaphragm moves the 
governor lever against the tension of the governor 
spring to close the throttle plates. The governed 
engine speed is held for constant load by centri
fugal force on the valve balanced against the tension 
of the valve spring. Any slight change in engine 
speed due to load restriction will cause the gov
ernor valve to react immediately, either increas
ing or decreasing the amount of air bleeding 
through the governor valve orifice. A change in 
the amount of air bleed will, in turn, cause an 
instant response from the diaphragm to increase 
or decrease the throttle plate opening.
When the 
accelerator is released, control is taken from the 
governor by the external throttle lever and the 
return spring in the accelerator pedal linkage 
closes the throttle plates to bring the engine to 
any desired lower speed.
Although the entire governor system is de
scribed, only the throttle actuating mechanism 
on the carburetor is included in theoverhaulpro
cedure presented in this manual. This portion of 
the governor can be cleaned and serviced readily, 
also the governor rotor can be serviced independly. 
See Holley Manual B-183 for servicing of governor 
control valve.
The approved method for properly overhauling 
a carburetor calls for the complete disassembling. 
A thorough cleaning and a careful inspection of 
each part is essential. Defective parts should 
be replaced with genuine Holley replacement parts 
and the carburetor should be carefully rebuilt. 
Care in rebuilding and accuracy in adjusting the 
carburetor will insure the same top quality per
formance engineered into every Holley Carburetor.
The overhaul procedure which follows can be 
accomplished with ordinary tools if a reasonable 
amount of care is exercised.
However, factory 
approved tools are recommended to facilitate 
overhaul and to prevent damaging of vital parts.
The special tools recommended for use in 
the overhaul of these carburetors are listed above:
Master Repair Kits contain Holley replace
ments for parts which are subject to wear or may 
be damaged in disassembly. The disassembly 
procedure includes instructions to discard all 
gasket and parts which have replacements in the 
Master Repair Kits. The proper kit for each 
carburetor is listed in the current Holley Carbu
retor Parts Catalog.
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