1973 Mustang Electric Choke Rewiring For Full Battery Voltage using wiper motor power circuit #63

In the link below a Motorcraft 2150 2v carburetor is shown with info re: setting its idle speed and idle air/fuel mixture. From the opening frames and through much of the video the cool air hose and tubing from the passenger rear of the upper carburetor, and warm air return tube wrapped in asbestos cloth leading to the choke housing can be clearly seen. The electric choke is also visible.

https://www.youtube.com/watch?v=UFdg44lI-xY
In a carburetor like the one in the link above on our 1973 Mustang Convertible, the stove warmed air from the passenger side exhaust manifold pulled into the choke housing was used to help warm the choke cap’s bi-metallic spring winding so the choke would open. The electric choke is used as supplemental choke heating device, where at temperatures below a certain point (I think 55 degrees) the choke element would use electrical current coming from Circuit #4, via a White wire with a Black Stripe, leading from the back of the alternator with its Stator Terminal to power the heater element.

Because the electric choke, beginning in 1973, was only a supplemental heating system the Stator terminal was an acceptable source of current when the engine was running. The Stator terminal only produces ½ of the alternator’s output voltage, and at that the current is Alternating Current (AC), as opposed to Direct Current (DC). When the electric choke is used as a supplemental heating system for the carb, the Stator voltage is adequate.

But, for aftermarket carburetors, such as the Holley carb on our 1973 Mach 1, being used in the this video, do not have a choke heater system using a stove warmed hot air source, and depend solely on the electric choke system to heat the choke cap’s bi-metallic spring to open the choke timely.. In those aftermarket electric chokes the choke heater element needs to get its power from a switched power source with full alternator output voltage. In this video I show one way of getting full battery/alternator switched voltage to the choke cap heating element terminal.

In this video I used the Windshield Wiper Motor's power feed (Circuit #63, a Red wire) to feed the Electric Choke heater element using a wire that is spliced into the Windshield Wiper Motor's wiring harness (not the main car harness) side of Connector #903 where the main wiring harness connects to the Wiper Motor’s harness. This eliminates changes being made to the car’s main wiring harness.

The wire used to connect to the wiper motor power circuit is spliced using a wiring splice locking device. The wire is then placed inside a plastic wiring conduit to prevent the wire from being damaged or scuffed in a way that could cause a short circuit to ground. It also makes the wiring change look clean, not hacked.

An alternative way of getting switch power with full battery/alternator voltage for 1972 and later Mustangs is done by splicing into Circuit #640 (Red wire with Yellow Hash tracer) used to power the carburetor Throttle Position Solenoid (TPS) that is present in some 1971 and later carburetors. Whether the carburetor uses a TPS or not, that circuit wiring is present in the wiring harness for 1971, 1972 and 1973 Mustangs and Cougars. The following link is a video showing where the TPS is located, as well as the Circuit #640 wiring harness lead location:

https://youtu.be/ljJ1uNy86wI
Another video that references the carburetor choke cap, and showing how to adjust the choke cap for leaner or richer choking is at the following link:

https://youtu.be/cTOjVPo-vCo

Видео 1973 Mustang Electric Choke Rewiring For Full Battery Voltage using wiper motor power circuit #63 канала Gilbert Hale