The Holley Carburetor Model 1901 is a dual
concentric downdraft carburetor. This dual carbu
retor can be considered as two carburetors built
side by side into one unit. Each side has a sepa
rate venturi, throttle plate and choke plate, idle
system, and main metering system. The carbu
retor Model 1901 is of a true concentric con
struction, for all major units and systems are
built around a common center. Concentric con
struction insures efficient operation under the
most severe operating conditions, such as driving
over steep grades and rounding curves at high
speed. Under these conditions, proper metering
is assured because of the location of the main jets
and power valve in the center and bottom of the
HOLLEY CARBURETOR MODEL 1901-FF FOR
1952 STANDARD TRANSMISSION MERCURY
HOLLEY CARBURETOR MODEL 1901-FFG WITH
GOVERNOR FOR 1952 FORD F-7 AND F-8 TRUCK
float chamber, which is itself centrally located.
Fully sealed within the air cleaner, the carburetor
uses only filtered air. This gives added protection
against plugging of passages and air bleeds with
Difficulties of hot starting are virtually eli
minated because of the position of the main body.
Mounting the main body in a manner which sus
pends it above the throttle body allows cool air
entering through the air cleaner to circulate freely
around and under the fuel bowl.
Added fuel required for acceleration is sup
plied by the throttle operated accelerating pump.
An "over-ride" feature of the accelerating pump
allows a prolonged discharge of fuel for smoother
acceleration. The accelerating pump linkage is
adjustable to allow a varying amount of discharge
to compensate for climatic changes.
A fully automatic power enrichment system
actuated by manifold vacuum delivers the added
supply of fuel necessary for high speed or full
On passenger cars, a thermostatically con
trolled automatic choke is used with this carbu
retor to assure instant starting in all weather.