Replacing the hot air choke on Quadrajet with electric

(originally posted 14 June 2010; recovered from 17 May 2013)

To replace your hot air choke on a M4MC Quadrajet – one that has the choke on the side of the carb – all you need is a later model OEM electric choke thermostat, say from a mid-80’s Quadrajet.

One electric choke that is suitable for all Chevy Quadrajet and Dualjet carburetors is part # CC139, available from The Carburetor Doctor.

The CC139 electric choke replaces the hot air choke exactly. Don’t use a gasket, because the choke is grounded through the carburetor.

The CC139 choke has a notch which is aligned with the front screw on the choke housing on the carburetor. This is a preliminary adjustment, but is usually pretty good for most applications.


The CC139 is an OEM design which contains two heater elements (high and low) and a thermal switch. No external sensors are required.

To wire the CC139 electric choke, connect it to power that is switched with the ignition or that is ‘ON’ when the engine is running. This can be the wiper motor feed, or direct from the alternator brown wire – use a fuse for safety.

That’s about all there is to it.  If you’re using this part in a car which already has electric choke wiring, you can use the original wiring.  Remember that in most 80’s GM cars and trucks the choke is wired through the oil pressure switch, so that if you have a bad switch you may not have power to the choke.

2 thoughts on “Replacing the hot air choke on Quadrajet with electric

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