S terminal on the alt. so it only has power when the engine is running. Key on power is no good cause the choke will heat and open without the engine running.
That's right the 'S' only puts out power when the engine is running. That's a moot point since 99.9% of all cars in the world use the key-on function. It's not generally a problem as long as the engines starts right up. And most do unless they have issues. Using the 'S' term for power is not compatible with all electric choke elements. To each his own. RS
The alternator stator lead is only live when the alternator is turning to produce current. It is an ac voltage,but the resister,which is the heater for the choke,could care less! So when you start your engine the alternator produces current,the tap for the choke is energized,and the choke opens as the electric coil in it heats up. You could hook your choke coil to a dc source,the ignition,for example,either way will work fine. Those of you who use the newer alternators will find it easier to hook your choke up to a switched dc source.
Just used to not using a key on feed in the trade. You can bet your ass someone will leave the key on before starting and open the choke. Yes either will work so long as you arent a dumbass and leave the key on prior to starting.
From Edelbrock FAQ Here's what Edelbrock has to say on the subject: Since my distributor (HEI internal coil) wire IS a switched 12V source direct from the ignition sw (not thru resistor wire) I don't see a problem with powering the choke off it unless maybe it's drawing too much current thru the ignition switch. I'll check the amps tomorrow. I'm anticipating relays for horns, headlights and elect fan someday. Hope I don't need yet another one. I like the short lead from the dist to the choke.
I stated the same thing as what Edelbrock has to say on the subject. So I'm not the only one. What is this obsesion about turning the key on leaving it on without starting the engine. Most people won't do that as they are going to start their engine right away. Who cares if it starts to open the choke right away. As long as it works and the engine starts up ok. Is anyone really listening? RS
Most electronic ignitions will over-heat if the key is lefy on without starting the engine. Do what you want - advice has been asked for and given - both by people with experience and the manufacturer. Your options and their effects are tied together so - make a choice - pick a consequence.
