where does the positive wire hook up to on a electric choke?

 

To an ignition-on source.

 

Look here in the eng compartment for that ignition on source.

Thank you mikeo0o0o0

 

On a factory Ford setup, I believe it should be to one of the terminals on the alternator, which actually provides half-voltage (~7V), and then only when the engine is spinning. On an aftermarket setup, it would be to 12V ignition-on power.

 

Any switched 12 volt source.
The one in the square in Richs' post above is the best spot for us Ford truck boys. It's close and works well.

 

On the factory set up the electric assisted choke is powered by the stator terminal on the alternator through a white w/ black trace wire. The stator provides ~7 volts AC to the choke.
Aftermarket carbs use 12 volts DC to power the choke.
Although it calls for 12V DC to the choke, in the past I've used the factory hook up without problems on aftermarket carbs.
(thanks for the "hat tip" Rich ).

 

Good clarification point Mike.
I'm a Holley guy so I automatically go to their default.

 

Switched.... That's the term I was looking for!

 

I'm scratching my head a little on that. IIRC Holley says that less than full voltage won't unwind the bimetal all the way. You remember anything like that?

 

Welcome to my old guy world

 

My '73 has 22k on it and the only thing that was added under the hood was an auxiliary brake line for trailer brakes. The plug that goes in the top of the alternator has a single wire closest to the front of the truck that goes to the factory electric choke.

 

Yeah Marc, that's what Holley says. I used to hook the choke up to a switched power source. One time I was in a hurry (don't remember why though...old age rearing it's ugly head I guess ) and just used the factory wire, the choke seemed to work just fine. The choke opened fully and didn't seem to take any longer, so, since then, I've used the factory wiring for the choke. If nothing else, it looks a little more original, I really hate crimped wire terminals .

 

Well shut my mouth and call me sweet pea. You learn something new every day.
That's a good one to know.

I hate crimps also. I'm trying to rid myself of that affliction.

 

if using an aftermarket Electric Choke, use an oil pressure switch so the choke is heated when the engine is running. I sawed a post here somewhere about it.

The point of the connection to alternator is so the choke is only heated when the engine runs.

 

I ran my choke wire from the original alternator system, now it looks like I need to run a new one to the 3G alternator now because the wire I used no longer has power anymore.

I just installed a Hobbs Switch for the fuel pump, I could just tie into the power side of the fuel pump relay. Not a bad idea.