PRINCIPLES GASOLINE/DIESEL FUEL SYSTEMS - OD1620 - LESSON 1/TASK 2
(7) FourBarrel Carburetor (figure 33). The fourbarrel or four
venturi carburetor consists of two primary venturis on a fixed throttle
shaft that are progressively linked to two secondary venturis that are also
on a fixed throttle shaft. The fourbarrel carburetor is commonly used for
V8 engine configurations, for the following reasons:
FIGURE 33. TYPICAL FOURBARREL CARBURETOR.
(a) The intake manifold may be divided to separate consecutive
cylinders.
(b) The carburetor serves the engine better throughout the entire
load and speed range.
g. Updraft, Downdraft, and Sidedraft Carburetion (figure 34 on the
following page). Carburetors may be built so that the airflow in the throat
is downward, upward, or sideways, as shown in figure 34.
h. Primer System. Some gasoline engines are fitted with a primer
system to aid cold starting. The primer system consists of a hand pump that
forces gasoline through a line to inject it at critical locations along the
intake manifold. The system is not used very much in modern equipment.
46
Previous Page
