Carburetor: Description and Operation

Carburetor:

Carburetor Parts List:

CARBURETOR
The Motorcraft 2150 is a two barrel single stage carburetor with two main assemblies and six operating systems. The main assemblies consist of the air horn, and the main body. The operating systems consist of the float system, idle system, main metering system, power system, accelerator pump system, and choke system. The carburetor also utilizes an altitude compensator.
FLOAT SYSTEM
The float system maintains an adequate supply of fuel in the fuel bowl for the fuel delivery systems. The single float chamber supplies fuel to all the carburetor bores. A float, brass needle seat and plastic tipped float needle with pull clip, are used to control fuel level in the float chamber.
IDLE SYSTEM
Each carburetor bore has a separate and independent idle system to provide the correct air/fuel mixture to the engine during idle and off idle operation. The idle system is required because air flow through the carburetor venturi is insufficient to obtain correct metering from the main discharge nozzles.
MAIN METERING SYSTEM
The main metering system supplies fuel to the engine during part to full throttle operation. The system mixes air and fuel in correct ratios during this range through plain tube nozzles and the venturi principal. The multiple venturi in each bore produces excellent fuel metering control due to its sensitivity to air flow.
POWER SYSTEM
The power system provides extra fuel enrichment to meet power requirements under heavy engine loads and high speed operation. The richer mixtures are supplied through the main metering systems of the carburetor.
ACCELERATOR PUMP SYSTEM
During quick acceleration with rapid throttle opening, air flow through the carburetor bores and intake manifold changes almost instantly. However, the fuel, which is heavier tends to lag behind causing a momentary leanness. To prevent this the accelerator pump system is used to provide the extra fuel necessary for smooth acceleration.
CHOKE SYSTEM
The choke valve mounted in the air horn above the primary carburetor venturi provides the correct air/fuel mixture enrichment for cold engine starting. The choke valve also assists engine running during the warm up period. The choke system uses an electric heat coil mounted in the choke housing, and this coil in combination with the choke valve and throttle position controls choke operation.
ALTITUDE COMPENSATOR
The altitude compensator uses an aneroid to sense atmospheric pressure and overrides the mixture system to prevent an over rich condition at high altitude.