electic choke

[gunnarunitover]

hey, i have a 72 powerwaggon with a 318 and a holley 4barrel carb with an electric choke. the problem is that the choke wont turn on. is there a way to test it or bypass it to a switch in the cab?

thanks,
steve

[Chump]

Turn the key to "ON" and test for approx 12volts on the wire that connects to the choke.

[acton mike]

I believe the choke gets its power feed from a switch that is controlled by oil pressure. In that way, the choke heater cold will not operate unless the engine is running

otherwise, the choke heater would come on as soon as you turned the key; if the engine did nor fire right away or you left the key on for a minute or so before trying to start, the heater would have in effect taken the choke off and the engine would be a bugger to start

[rolnblok]

Let me see if I understand what you are saying,

Your 12 volt wire runs through an oil pressure switch that is open with out oil pressure. It seems that this would require cranking the motor for a short period to build oil pressure before the choke could even try to function.

I understand the logic, but that seems a little counter productive. I want my choke to work immediately so the vehicle will start when I want it to. Anyway, crank the engine until you have oil pressure enough to complete the circuit. Then test for 12 Volts. If there is no voltage, the oil pressure switch could be bad. The other option then is to take the "hot side" off the oil pressure switch and test it for 12 volts with the key on as Chump suggested.

Holley is pretty specific that they want 12 volts to their electric chokes. (though it likley will be slightly higher when the engine is running) Where does the power to the oil pressure switch come from? When i ran my 12v wire to my truck avenger, i came of the 12volt "in" side of the ballast resistor. Works like a champ.

Hope this helps some.

[buck99]

The 12 volt is to take the choke off after it starts.

[Chump]

I believe the choke gets its power feed from a switch that is controlled by oil pressure. In that way, the choke heater cold will not operate unless the engine is running

otherwise, the choke heater would come on as soon as you turned the key; if the engine did nor fire right away or you left the key on for a minute or so before trying to start, the heater would have in effect taken the choke off and the engine would be a bugger to start

Yes, in the later years, this is a 72 and the oil pressure switch is a 1 wire switch and acts as a variable resistor to ground, only for the gauge. The reasons you stated above are true and you'll find that when people have trouble with this type of choke setup it is actually the driver that is at fault for poor maintainance or a vacuum between the ears. I agree that the oil pressure switch arrangement is better for some and if feasible on older models. :):)

FYI-some people are proud when they say "I ripped all that junk out of there and put in a cable and drilled an un-sightly hole in the dash rather than educate myself". That's why there are so many older vehicles with buggered up carbs. Later years also used an electrical choke assist switch but mainly for emissions.

The "RUN" circuit is on a 16ga Red wire/s on the engine harness and on 1 side of the ballast resistor.

From Holley online FAQ...

QUESTION Where do I hook up my electric choke?
ANSWER The positive (+) spade on the choke cap needs a wire from a 12v that is hot anytime the key is on ( from fuse box to anything that is only hot with the key ) The neg. (-) spade on the choke cap will go back to the carb for a ground.

[rolnblok]

Thanks for the education. Guess I was confused. :dunno: It all makes more sense now. The 12volt wire heats (via resistance) the bi-metal strip forcing it to open the choke. Some type of an oil pressure switch could then make sure the choke is only heating after the motor is running and thus prevent the choke from coming off too soon.

[DiverDwnPowrRam]

FYI-some people are proud when they say "I ripped all that junk out of there and put in a cable and drilled an un-sightly hole in the dash rather than educate myself". That's why there are so many older vehicles with buggered up carbs. Later years also used an electrical choke assist switch but mainly for emissions.

Well said Chump...well said

[Speed Dragon]

FYI-some people are proud when they say "I ripped all that junk out of there and put in a cable and drilled an un-sightly hole in the dash rather than educate myself". That's why there are so many older vehicles with buggered up carbs. Later years also used an electrical choke assist switch but mainly for emissions.

Well said Chump...well said+1, I hate that crap, my '80 had that done to it :mad: