Electric Choke Question

[Roy]

I purchased a crate engine that came with a Holly carb with an electric choke.

Question: Do I wire the electric choke with a (+) wire that is energized when the ignition is turned on, OR

Do I wire the electric choke through a thermostat that then is wired to the electric choke?

My concern is "Does the electric choke when the engine is warmed up if it does not get a signal from a temperature thermostat?" Does the electric choke have it's own internal thermostat that controls the opening and closing of the choke mechanism?

If I only need to connect a wire that is activated by the ignition, which wire is the best to use? Can a splice a wire off the (+) feed wire to the distributor? How about the (+) wire that feeds the blower fan that is always "on" when the ignition is "on"?

Thanks.

roy.truelsen@verizon.net

 

[GerryLP]

Roy,

The electric choke is a mechanism that provides relatively richer fuel mixture to overcome the lack of heat in the intake manifold which helps the atomization of the fuel, and it uses electric current through a bi-metalic coil (or a variation of this principle) to open the choke plate and stop supplying the richer mixture.

I recommend that the wire be connected to the alternator 12V feed, so that it will ONLY receive 12v current when the engine turns. If you connect it to another source like the ignition or fan, then it will not work well at all, for some ignitions will not provide the full 12v current that the thermostat needs. If its on the fan blower, the it will start receiving current when the key is turned (i.e. to play the radio while one's love one goes to Target...lol). This will nullify the thermostat, for it is designed to warm-up the bi-metalic coil in short time, and then the carb will not get the benefit to run relatively richer in those cold mornings or cold nights.

One draw back on electric choke is that if one turns off the engine long enough for the thermostat to cool, then the next time shortly thereafter you need to start the engine again it will run rough due to added fuel enrichment. So to get around this, they came up with the divorced-choke design. This type will only make the carb go into choke mode when the engine is cold. For this, they mounted it on the exhaust manifold or even the intake manifold. However, because of the heat, the coils used do require added maintenance to keep it free from heat-generated corrosion.

I believe that there is an available heat pod of sorts that will ONLY allow the 12V current to flow to the carburator if the engine is cold.

 

[Roy]

Electrical Source for Electric Choke

GerryLP,

When I checked the elctrical connections at the alternator I found that the two (+) wires were constant "hot" and not switched by the ignition. This could be an error in the wiring but if it isn't, then these wires would provide a constant (+) feed to the electric choke, eventually drawing down the battery. Do you agree?

Thank you very much for your imput.

roy.truelsen@verizon.net

 

[GerryLP]

Yes! I would agree. I need to check the routing on my green thermnostat cable to provide you with a more accurate asnwer.

 

[JohnZ]

Wire it to an ignition-switched full 12V feed (don't use the coil + terminal, as that only gets 7-8 volts due to the resistance wire that feeds it). There's usually a cavity in the fuse block with a spade terminal in it that's marked "Ign" - you can feed it direct from there.