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PART 10-4- MOTORCRAFT MODEL 2100 CARBURETTOR
10-35
INTERNAL
BOWL
VENTS
CURB IOL
E
AOJU
STIN
G SCREW
FIG. 2- Motorcraft Modei2100-D, 2- V
CHOKE
PLATE
CHOKE OIAPHRAGM
ASSEMBLY
CHOKE
HEAT
TUBE
CONN
ECTION
V1200-A
Carburetor - Left Rear 3/4 View - Typical
. .
FUEL
FIG. 3-Fuel Inlet
System
the guides on each side of the fuel
bowl. The retainer fits into a groove
on the outside of the fuel inlet nee-
82598-A
die seat. The ends of the retainer are
hooked over grooves on opposite
ends of the float shaft.
The fuel bowl is internally vented
into the air cleaner. It is also exter-
nally vented to the atmosphere.
AUTOMATIC CHOKE SYSTEM
The choke plate, located in the air
horn above the barrels, when closed,
provides a high vacuum above as
well as below the throttle plates. With
a vacuum above the throttle plates,
fuel will flow from the main fuel sys-
tem as well as from the idle fuel sys-
tem. This provides the extremely rich
fuel mixture necessary for cold en-
gine
operation.
The carburettor choke shaft
is
linked to a thermostatic choke con-
trol mechanism mounted on the main
body (Fig. 4).
The linkage between the choke le-
ver and the throttle shaft is designed
so that the choke plate will partially
open when the accelerator pedal is
fully depressed. This permits unload-
ing of a flooded engine.
The automatic choke is equipped
with a bimetal thermostatic spring
and a vacuum piston
(Fig.
4). The
bimetal thermostatic spring mecha-
nism winds up when cold and un-
winds when warm. When the engine
is cold, the thermostatic
spring,
through attaching linkage, holds the
choke piston upward and the choke
plate in a closed position prior to
engine start. Manifold
vacuum
chan-
neled through a passage in the choke
control housing draws the choke
vacuum piston downward, exerting an
opening force on the choke
plate.
When the engine is started, mani-
fold vacuum, acting directly on the
piston located in the choke housing,
immediately moves the choke plate
against the tension of the thermostat-
ic spring to a partially open position
to prevent
stalling.
As the engine continues to oper-
ate, manifold vacuum draws heated
air from
the inlet manifold heat
chamber. The amount of air entering
the choke housing is controlled by
restrictions in the air passages in the
carburet tor.
The warmed air enters the choke
housing and heats the thermostatic
spring, causing it to unwind. The ten-
sion of the thermostatic spring grad-
ually decreases as the temperature of
the air from the heat chamber rises,
allowing the choke plate to open. The
air is exhausted into the intake mani-
fold.
When the engine reaches
its
nor-
mal operating temperature, the ther-
mostatic spring exerts tension on the
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