Electric choke wiring 2100 carb.

[Jimboss77]

Hey guys. Just rebuilt my 2100 which has both the exhaust hot air tube and electric ‘assist' terminal. Engine is running great now with the fresh carb and elimination of a couple of vacuum leaks from the decommissioned egr system. Anyway I'm looking for clarity on both where the wire to the choke should be connected for power and what exactly does this electric assist do? History…..when I got this machine most of the wiring, especially ignition, had been been butchered so I won't be surprised if the wire to the choke as currently connected is wrong.

I have run the engine from a cold start with the hot air tube disconnected and the wire connected to the choke housing from the ‘S' terminal on the solenoid. The choke never opened. I disconnected the wire and connected the hot air tube and the choke worked as it should. This raises the question of what does this electrical connection do for the choke and where should it be connected? Do I even need this connection? Was it part of the egr?

 

[Slowleak]

The electric assisted chokes connect to the stator terminal on the alternator. That way they only get power when the engine is running, not when the key is left on. They function above a certain ambient temperature to open the choke faster to reduce emissions.
For example, on a 70 degree day your choke will be closed on a cold engine. The electric assist will open the choke quickly since the choke is not really needed, or needed for long. That reduces emissions. On a 20 degree day, the electric assist does not “assist”, and the hot air tube does the work of warming the choke. That gives the engine time to warm up before the choke opens. You do not have to use it.

 

[Jimboss77]

Slowleak you answered all my questions, thanks! The way it operates makes perfect sense. Since I live in the South and drive my Bronco on mostly warm days I will connect the choke to the stator as designed and release the choke sooner.

 

[blubuckaroo]

I'm sure someone will correct me if I'm wrong, but I don't think any Early Bronco came with an electric or electric assist choke.
Yes it's true that Ford used the stator terminal on the alternator for electric chokes on some vehicles, but not on Broncos.
I'd say that if your Bronco has a 2100 carb with a wire terminal on the choke cap, it's either aftermarket or from another car.
The question now is whether it's Ford or aftermarket. That's important, because Ford's electric choke was made for the 7 volts from the stator terminal. Aftermarket chokes and carbs need 12 volts.
Sure there are some owners who use the 7 volt stator terminal on aftermarket chokes or carbs, but the choke operation would certainly be delayed accordingly.

 

[Slowleak]

Broncos did have electric assisted chokes, wired to the stator, starting in 1973 when Ford came out with them. The chokes open in about 45 seconds as opposed to minutes with just the hot air tube. They only work when the ambient temp is above 60 degrees. A 12 volt cap may take a little longer, but correct 7 volt AC replacements for Autolites are available. I have one on my ‘77. I spent hours researching and testing it. It works perfectly.

The OP has a ‘77 which would have a 2150. Maybe it was retrofitted with a 2100. Either way, a ‘77 would have the hot air tube, and an electric assist choke cap wired to the stator. That setup works fine on a 2100…

 

[blubuckaroo]

Broncos did have electric assisted chokes, wired to the stator, starting in 1973 when Ford came out with them. The chokes open in about 45 seconds as opposed to minutes with just the hot air tube. They only work when the ambient temp is above 60 degrees. A 12 volt cap may take a little longer, but correct 7 volt AC replacements for Autolites are available. I have one on my '77. I spent hours researching and testing it. It works perfectly.

The OP has a '77 which would have a 2150. Maybe it was retrofitted with a 2100. Either way, a '77 would have the hot air tube, and an electric assist choke cap wired to the stator. That setup works fine on a 2100…

Thanks for the correction.
I just dug through all my Bronco manuals and didn't see anything about a terminal on electric chokes.
My '77 Motorcraft 2150 didn't have it.

 

[Slowleak]

The ‘77 Ford manual mentions, and pictures it, in several places. I still have the original from mine. I have read that all Fords got this in ‘73 but who knows….

 

[Jimboss77]

I always learn something new when I read or post to this sight, the biggest being that after 50 years on the road it is sometimes difficult to identify what's original and what's not on these machines. My Bronco is a 77 but the engine came from a 70's model Mustang. Not sure what year, maybe one day I will crawl under and remove the starter to get the casting numbers from the block butÂ…Â…not today My carb is a Motorcraft 2100 and I'm guessing it came from the donor Mustang but no way to know. Since all the front end dress was Mustang ( dip stick, timing pointer, balancer) I'm guessing the intake and carb as well. I've been cleaning up the wiring, vacuum hose routing, heater hose routing, old egr components etc.. along the way and this choke mystery wire was one of those items. When they did the swap years ago they just laid and routed stuff in the easiest position not thinking about servicing or looks. Can you tell me where this choke wire was routed to the alternator to be out of the way and safe?

 

[Slowleak]

On mine it goes down from the choke, rests on the inside lip of the valve cover, and drops down the front of it to the alternator. Several folks on here have EB's that are virtually untouched under the hood. They may be able to verify the routingÂ….

 

[blubuckaroo]

The ‘77 Ford manual mentions, and pictures it, in several places. I still have the original from mine. I have read that all Fords got this in ‘73 but who knows….

Yes, I looked at a couple of parts catalogs, and some came with electric and some climatic chokes. Mine is a CA car. Maybe those are different.

 

[jckkys]

I bought my '77 new and know Slowleak is absolutely correct in every detail. The wire supplying power to the electrically heated thermostatic choke cap is short and direct to the stator post on the alternator. The connection is a push on type. I think it was white with a black stripe.

 

[blubuckaroo]

I bought my '77 new and know Slowleak is absolutely correct in every detail. The wire supplying power to the electrically heated thermostatic choke cap is short and direct to the stator post on the alternator. The connection is a push on type. I think it was white with a black stripe.

I'm the original owner of our '77 too and there was no terminal or wire on the choke cap.
There is now that I've put on the Edelbrock 1305 carb.
But like I said, it's a CA car, and there were differences back then. There were no 50 state cars.

 

[Rustytruck]

My California 1974 Bronco came with the stove pipe and electric choke assist.

 

[DirtDonk]

I'm the original owner of our '77 too and there was no terminal or wire on the choke cap.

Is it still the original wiring? If so look on the back of the alternator for the white with black stator wire. Then look up in the engine harness up near there top of the manifold and see if you can find it terminated there somewhere.
It was their habit back then, as it probably still is today, to use the same wiring harness on all vehicles whether they got all the options or not. Just like having the dome light and map light wires without a dome or map light installed.