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10-14
PART
10·2
STROMBERG CARBURETTOR BV2-
200,250 IV
6 CYLINDER ENGINES
Section
Section
Page
1.
DESCRIPTION AND OPERATION ...
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Page
10-14
10-14
10-14
10-17
10-17
10-17
10-18
10-19
3. REMOVAL, MAJOR REPAIR OPERATIONS AND
INSTALLATION
Description
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10-20
10-20
10-20
10-21
10-21
Operation
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Removal
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2. INVEHICLE ADJUSTMENTS AND REP AIRS
Carburettor Adjustments
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Disassembly
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Cleaning and Inspection
Initial Idle Speed Adjustment
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Assembly
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Idle Limiter Cap Replacement
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Carburettor Repairs
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0
DESCRIPTION AND OPERATION
DESCRIPTION
The Carburettor (Figs.
1 and 2)
consists of three main assemblies, the
<uppen Air Horn
,
the <centre1 Main
Body and the <lower 1 Throttle
Body.
The upper air horn assembly con-
tains the power piston assembly, the
idle vent vah·e and choke
valve.
The centre main body contains the
major metering components of the
carburettor
:
the main and idle fuel
systems the power by-pass system.
the accelerating pump assembly, the
float chamber and the fuel inlet system.
FIG.
1-3/4 Left Rear View
The lower throttle body contains the
idle-mixture-adjusting screw and the
throttle
valve.
OPERATION
The engine speed is controlled by
the proportion of fuel and air deliv-
ered to the cylinders for all engine
operating conditions.
Air is drawn into the carburettor
air
horn by manifold
vacuum.
As the
air passes through the carburettor on
its way to enter the cylinders, a re-
duced pressure is created at the fuel
discharge outlets.
The fuel bowl is vented to atmos-
phere at closed throttle and to car-
burettor air inlet pressure through a
vent tube in the upper air horn at
all other throttle positions. The high
air pressure exerted on the fuel in
the chamber forces fuel to travel up
through the fuel discharge channels
and out into the air stream passing
through the carburetor. The fuel and
air are mixed at this point and dis-
tributed to the engine cylinders for
combustion.
FUEL INLET SYSTEM
The fuel inlet system (Fig. 3) of
the carburettor maintains a prede-
termined fuel level in the fuel bowl.
The fuel level in the chamber is
extremely important to carburettor
calibration. If the level of the fuel
in the chamber is below the specified
setting, a lean fuel air mixture will
result. A rich fuel air mixture
will
occur from a higher than specified
fuel level. The entire calibration of
the carburettor is disturbed if the fuel
level is not set as
specified.
Fuel enters the chamber through
the fuel-inlet needle-valve-and-seat
assembly. The amount of fuel enter-
ing is regulated by the distance the
needle valve is moved off the seat
and by fuel pump pressure. Correct
fuel pump pressure is required to
maintain the carburettor fuel level
within the specified
limits.
The fuel level
is
maintained at a
pre-determined level by the float and
lever assembly which controls the
movement of the needle valve. The
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