I would say you have it right.

The choke needs 12v switched....”start” and “run” only.

Nos681 wrote:

The choke needs 12v switched....”start” and “run” only.

switched and under key are the same ?  maybe i have inverted definition .... I used the center pin of ignition switch . the one threated . this turn on when i turn on the key without cranck . Is correct where i pick up for electric chocke ?  
thanks 

josh-kebob wrote:

I'm runnng an edlbrock 1403 with electric choke. I ran the red wire to the fuse box and tapped into the assesory fuse using the Napa fuse adapter shown in the pic. Works perfect and was easy except for the part where I had to stand on my head to see the fuse box.




upload images

Yes , i pick up from same wire but coming from switch . Is not under fuse but i think is good too.  My worries was about beeing hot all the times , but all tells   me is all right .  thanks ! 
 

The spring in an automatic choke is a bimetallic strip that reacts to heat with different expansion rates.  When it heats up it unwinds which opens the choke.  When it cools down it winds back up pulling the choke back closed.  An electric choke is using current as the source of heat while the hot air chokes capture heat from the exhaust manifold.  Either way, the ideal source of heat will only be generated when the engine is running and not simply when the key is switched on.  Using a key on source is expecting the engine to start right up because that choke spring is going to start heating right away.

Since a choke is meant to assist with the engine starting, it should not start opening before the engine has actually started.  On my Mustang, I wired it to a fused 12v wire from the battery through a relay that is triggered by the alternator stator terminal.  This setup works like the hot air choke except that it uses electrical current as a heat source instead of hot air from the exhaust.  This current is only fed to the choke while the engine is actually running.  The difference will only really be present during cold weather if the engine is not wanting to start right away.
 

You have the operation of the electric choke backwards.  The choke closes when it's bimetallic coil is cold from not being energized.  It opens when it warms up after being energized.

To "set" the choke, you depress the gas pedal one time before the first attempt at starting the engine.  When the choke bimetallic coil has fully cooled from not being energized, it coils up and attempts to pull the choke blade closed.  However, the fast idle cam actually blocks the blade from fully closing,  When you depress the gas pedal, the fast idle cam is pulled out of the way allowing the choke blade to snap fully closed. 

You’re correct Rufus.

When engine cools down, the bimetallic strip coils back up to try to close, hindered by fast idle cam.
That’s why you step on gas at least once fully to allow it close for start up. (Technically a predetermined gap.)
As engine is started, the 12v to the coil starts to heat up and unwind...in the full open direction.
When engine and choke coil are at operating temp, should be full open.
It’s common to make minor adjustments in places where temperatures change seasonally.
Electric chokes require less fiddling around with seasons as compared to heat operated (engine/intake/exhaust chimney) chokes.

Last edited by Nos681 (5/19/2020 4:48 PM)

Alessandro wrote:

This is still something that create debate and confusing who has new style alternator  (1 wire )  .
i stll have some doubt  because , from Edelbrock tech center , reply my question that many don't agree . 
So i am little confused . 
Alternator write .:  this connection is provided for el . chocke . 
edelbrock write :  do not use alternator to pick up el. chocke 
edelbrock write : 12 volt key switched  , must be hot all the times , also when running 
Folks says :   12 volt switched but must be hot only on cranck .  After engine is running must shut off .
folks says :  from S teminal of solenoid 
Edelbrock write  : do not pick up from S terminal of  solenoids bcause volts are variable . 
folks says .  :  hook up from S side of alternator . 
edelbrock write  do not pick up from S side of alternator because if are 10 v or 9 volts chocke will not work properly
 
Now i have it connected with 12 v switched , but hot all the times . Seems working as supposed to be , after warm up at first touch of pedal ,  chocke is disengaged . 
Can you sign a light in this dark matter ...?  i think the question is : This chocke needs 12 volts all the time , also after cranck  , or  shut off after engine is running ? 

Thank you ! 

 

A quick electrical lesson. Wattage is directly proportional to heat or BTU's. If something is designed to work on 12 volts and you reduce the voltage to one half, 6 volts, you have reduced wattage not by one half but by one quarter. That is one quarter of the heat. So you can see reducing voltage even slightly is going to have a big effect on heat. Electric chokes designed to operate off the alternator run at a lower voltage then a lot of aftermarket carburators designed to run off 12 volts such as your Edelbrock. That's why it didn't work very well off the S terminal.

You can substitute numbers and play.
I had to write it down to remember it myself.

E= volt
I= amp
R= resistance
P= watt

Arrows indicate increase, decrease, remains same.

Last edited by Nos681 (5/20/2020 10:49 PM)