provide fuel for smooth quick acceleration a double spring pump plunger
is used in the Model "B" Carburetor.
The rates of compression
of the top spring versus the bottom spring
is calibrated to insure a smooth, sustained
charge of fuel for acceleration.
shown on Figure 2, to exclude dirt all fuel
for the pump system first passes through the
pump screen (4) in the bottom of the float
bowl. It is then drawn past the ball check (5)
into the pump well on the intake stroke of the plunger. Upon acceleration
the force of the pump plunger seats the ball check (5) and
forces fuel up the passage (6).
The pressure of the fuel
lifts the pump outlet ball check
and spring (7) from its seat. The fuel is
then sprayed on the bottom edge of the venturi
by the pump jet (8) and delivered to the
targeting of the Pump Jet is required
greater driving ease the pump plunger