Figure 4-10. Mechanical Positive Pump Installation.
rocker arm as the fuel pump and is a nonpositive type
f. Electric, Bellows-Type (Fig. 4-12). The
diaphragm pump. At times when manifold vacuum alone
bellows-type electric fuel pump works basically the same
is sufficient to operate the windshield wipers, the
as the nonpositive-type mechanical pump. The
diaphragm will be held up against the diaphragm spring
difference is that it is driven by an electric solenoid rather
by atmospheric pressure, rendering the pump
than a mechanical cam-shaft. Operation is as follows:
Figure 4-11. Double Action Pump.