PLATE AS 9X8122 - Caterpillar

The carburetor combines gas and air in order to establish a combustible fuel mixture.The IMPCO carburetors on this application are for use on a low-pressure gas fuel system.The fuel jet and the fuel valve are interchangeable on the carburetor.
Illustration 1 g02393637
Flow of air and gas into the carburetors (1) Filtered inlet air (2) Gas (1-2) Air/fuel mixture
Illustration 2 g02394279
Section view of the carburetor and the throttle in the open position (3) Spring (4) Fuel valve (5) Fuel jet (6) Diaphragm (7) Passage (8) Power valve (9) Throttle controlWhen the engine is stopped, spring (3) presses the O-ring seal of fuel valve (4) against fuel jet (5). No fuel can enter the mixing chamber of the carburetor.Power valve (8) can be adjusted to restrict the amount of fuel that enters the carburetors.As the engine is started, the intake strokes of the pistons generate a vacuum in the cylinders. The vacuum draws filtered inlet air (1) into the carburetor. This vacuum pulls through passage (7) and acts on diaphragm (6). As the force of the vacuum on the diaphragm overcomes the force of spring (3), the fuel valve moves away from the fuel jet. Filtered air and gas (2) is then allowed to enter the mixing chamber and combine. As the air/fuel mixture (1-2) passes through the turbocharger compressor and aftercooler, the air/fuel mixture becomes thoroughly mixed. The volume of the mixture that is allowed to enter the engine is controlled by the throttle control (9) .When the engine is operating at a constant load and speed, the position of the diaphragm is constant. The diaphragm only moves when the demand for fuel varies.