ROCHESTER CARBURETORS
Bulletin 9D-7 August, 1951
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Bulletin 9D-7 August, 1951 Model
"BB"
Page 6 |
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ROCHESTER PRODUCTS, DIVISION OF GENERAL MOTORS, ROCHESTER, NEW YORK |
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FLOAT SYSTEM To aid in maintaining the correct fuel level under all conditions the carburetor employs twin floats. It is of the utmost importance that the floats be adjusted carefully and accurately. (See Figure 5)
SEE ADJUSTMENT BULLETIN FOR CORRECT FLOAT SETTING. |
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ACCELERATING PUMP SYSTEM When the throttle is opened suddenly the air flow and manifold vacuum change almost instanteously, while the heavier fuel tends to lag behind causing a momentary leanness. The accelerator pump provides the additional fuel necessary for smooth operation on rapid acceleration. (See Figure 6) |
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MODEL "BB" FLOAT SYSTEM
Figure 5 |
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A double spring pump plunger is
used on the model "BB" carburetor. The rates of compression of the
top spring versus the bottom spring are calibrated to insure a smooth,
sustained charge of fuel for acceleration.
On the pump intake stroke, fuel
passes through the pump inlet screen, unseats the inlet ball, and fills
the pump well.
The accelerator pump, being
connected directly to the
throttle, moves at the slightest change in throttle opening. The
force of the pump plunger upon acceleration seats the inlet ball, forces
fuel through the outlet channel which unseats the spring loaded outlet
ball and then discharges through the pump jets, into the main air
stream.
NO TARGETING OF THE PUMP JETS IS REQUIRED.
MODEL "BB" PUMP SYSTEM
Figure 6
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