Can someone tell me how this thing is supposed to work? Does the choke come on when the power is sent to the coil, thus forcing the flaps into a closed position (choke on). Or when the power is sent to the coil, does it force it open (choke off)?

the choke heater wire connects to the Electric choke unit. When you start the engine 12-15 volts is supplied to the unit causing it to warm up the internal spring which then loses tension allowing the choke butterfly to open up.

Hope this helps.

Brian P. :)

So, if the choke wasn't hooked up, would the butterfly stay open or closed?

It would stay closed.
Voltage required for it to open.

As noted, when cold, the choke will be all the way closed. There is a diaphragm with a rod on the side that holds the choke open a bit so the car will run. It's called the choke pulloff. Dial it so the choke is at a 45° angle or so to start.

As noted, when cold, the choke will be all the way closed. There is a diaphragm with a rod on the side that holds the choke open a bit so the car will run. It's called the choke pulloff. Dial it so the choke is at a 45° angle or so to start.

Thanks Todd. So, on these electric chokes, what causes the choke to open up. Is it the engine heat or is it the actual coil heating up from the 12 volts?

Thanks Todd. So, on these electric chokes, what causes the choke to open up. Is it the engine heat or is it the actual coil heating up from the 12 volts?
It's the heat from the 12 volts.

Keep in mind, as Todd said, when it's cold outside is the only time the choke will be closed all the way. Above 65* F outside and it will barely be closed. IIRC, 65* is supposed to be the optimum temperature to set the choke.

Some were powered through the alternator and some through an oil pressure switch, so a simple 'key on' won't heat them up.

It is an electric choke, and as mentioned, the 12V sent to it heats it, and the heat of the engine itself does as well. They go out of adjustment easily.