I'm confused by the choke on my engine. It seems to work, but I want to know how it works. It's not electric as far as I can tell, and it doesn't seem to be hot air. Does it just work on the heat of the manifold below it? There's a little deal sticking off that looks like it should have a wire on it, but it hasn't since I got the car. It's mounted on a Carter 2 BBD on top of a 318. Picture attached. Thanks for any info you can give me!

 

Yes it will work off the heat of the manifold...
Yes it use to have a wire that went to a resister toward the back if the manifold.... You can google them and the wiring.... Cheers...