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ROCHESTER CARBURETORS Bulletin 9D-8 August, 1951 |
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Bulletin 9D-8 August, 1951 Model
"BC" Page 6 |
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ROCHESTER PRODUCTS, DIVISION OF GENERAL MOTORS, ROCHESTER, NEW
YORK |
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FLOAT
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FLOAT SYSTEM
The Model "BC" Carburetor employs
the conventional float needle and seat to control the fuel level in the
float bowl. In accordance with concentric float bowl design, dual floats
are used to maintain fuel level. (As shown in Figure 5) For some
applications a small clip connects the float needle to the float. In this
manner, the float needle is drawn from its seat by the float as the fuel
level lowers, thereby permitting an ample entry of fuel into the bowl to
meet increase engine demand.
This
feature also serves to retract the needle from its seat, if for any reason a
gum residue might tend to
cause a sticking condition. |
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Figure 5. Float System |
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PUMP SYSTEM
To provide fuel for smooth quick
acceleration a double spring pump plunger is used in the Model "BC"
Carburetor. (As shown in Figure 6.) The rate of compression of the top
spring versus the bottom spring is calibrated to insure a smooth,
sustained charge of fuel for acceleration.
To exclude dirt, all fuel for the
pump system first passes through the pump screen in the bottom of the
float howl. It is then drawn past the ball check into the pump well on the
intake stroke of the plunger. Upon acceleration the force of the pump
plunger seats the ball check and
forces fuel up the discharge passage. The pressure of the fuel lifts the
pump outlet ball check from its seat. The fuel is then sprayed on
the edge of the Venturi by the pump jet and delivered to the
engine. |
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Figure 6. Pump System |
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