TILLOTSON HU Series, Руководство по обслуживанию

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5
INTERMEDIATE OPERATION
Fuel is delivered into and through the carburetor in the same manner as when the engine is idling. However, as
the throttle opens and engine speed increases, more fuel is supplied to the engine by valving in the secondary
idle discharge port located immediately behind the throttle shutter.
As the throttle shutter continues to open and engine speed increases, the velocity of air through the venturi
creates a low-pressure area at the venturi throat and diminishes the suction on engine side of the throttle shutter.
When the pressure at the venturi throat is less than existing within main diaphragm fuel chamber, fuel is drawn up
through high speed mixture orifice and out main fuel discharge port into air stream entering engine intake.
HIGH SPEED OPERATION
As the throttle shutter progressively opens from intermediate position to full open position, the air velocity through
the venturi increases and fuel is metered up through high speed mixture orifice and main fuel discharge port in
accordance with the power requirements of the engine. The action of the main diaphragm is the same as
previously described with suction required to operate the diaphragm being transmitted through the main fuel
discharge port.
SUPPLY FUEL
ATMOSPHERIC AIR
PUMP IMPULSE AIR FUEL UNDER VACUUM
FUEL UNDER PRESSURE