Electric Fuel Pump for Classic Cars

Electric fuel pump

Electric fuel pumps are used on some heavy duty equipment such as trucks and buses.

The fuel pump contains a flexible, metal bellows that is operated by an electro-magnet.

When the electro-magnet is connected to the battery by turning on the ignition switch, it pulls down the armature and thereby extends the bellows.

This produces a vacuum in the bellows.  Fuel from the fuel tank enters the bellows through the inlet valve.  Then as the armature reaches  its lower limit of travel, it opens a set of contact points, this disconnects the electro-magnet from the battery.


Electric Fuel Pump for Classic Cars

Electric Fuel Pump for Classic Cars

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The return spring, therefore, pushes the armature up and collapses the bellows.  This forces fuel from the bellows through the outlet valve into the carburetor.

As the armature reaches the upper limit of its travel, it closes the contact, so that the electro-magnet is again energized and pulls the armature down once more.

This series of actions is repeated as long as the ignition switch is turned on.

The electric fuel pump then supplies fuel to the carburetor on demand from the carburetor, the same as the mechanical pumps, except that instead of being driven by a rocker arm off of a camshaft eccentric, it is
actuated by the electro-magnet.

Related Articles – Carburetor Idle System of Classic OLD Cars


The fuel pump is such that it delivers fuel to the carburetor only on demand from the carburetor.  And how was that done ? 

The float in the carburetor regulates input to the carburetor, and the spring on the fuel pump regulates its output.  As for answer –  only the combination pumps have as one side a vacuum pump which actuates the wiper motor.

Related Posts – How Carburetors Works in Old Classic Cars


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Article Source : This article courtesy should goes to Auto Mechanics Autodology – Technical instruction manual by System Operation Support.