What Does the Solenoid Do on the Bottom of a Carburetor?

by David Roberts
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When you turn the key in your vehicle, a small electrical charge is sent to the solenoid on your starter and on the solenoid near your carburetor. This electrical charge forces the coil to move the piston inside that completes the electrical circuit.


A solenoid is a mini-electromagnet. It contains a piston surrounded by a metal coil. When "activated" by an electrical charge, the piston snaps into place between two electrical contacts and completes the circuit that sends electrical energy to the component it is attached to. There is a starter solenoid, and, in some vehicles, a carburetor solenoid.

Starting the Engine

Your carburetor's power source is the battery in your vehicle. Without the action of the solenoid, the battery would power that carburetor even when the engine is shut off. The solenoid receives a charge when you turn the ignition which activates the small electromagnet inside and completes the circuit, turning on the carburetor. This allows you to start the vehicle because the carburetor is ready to start mixing the fuel and air combination that makes the engine turn on.

Stopping the Engine

When the engine is shut off, the solenoid cylinder falls to the bottom of the coil surrounding it, ending the power flow to the carburetor. With no power to continue mixing the fuel and air, the engine chokes and stops running altogether.

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