Use Relay to Power an Electric Choke 

Great tips on the way this is wired. Initially, I wanted to trigger the relay off of the alternator so that the choke wouldn’t be heating up unless the alternator is spinning. That is to say, should the engine stall, the choke would begin closing rather than continue to open. It sounds like this could be done by simply grounding pin 85 on the relay and tapping into the brown wire for pin 86. This was my preferred way of wiring it, but the ignition coil was the quick and easy way to power the relay without having to decipher how the alternator was wired.

@@mebordernoneya8484 Yes, Pin 86 can go to the brown field wire behind dash or IP Cluster. The original internally regulated Delco alt control ground to rotor at 400hZ below any AM radio stations, but use a “Y” connect stator. Magnetism remains to some level for months but use a key on thru the battery light, to alternator excites it to ON state. Field becomes B+ and goes to dash bulb. With 12+ volts on both side that light simple can’t come on. As for a running engine dying, the choke (If warmed) takes a long time to actually close. Plus, at WOT the linkage actual opens choke to allow for warm engine restart, just like EFI, but it just shuts injects off at 95%. Both keep from flooding. CCC started in the 80’s and I have a factory service manual for 86 “A-Body” that I will have to look at. Honestly I can’t remember all! Imports are the easiest, because they simply tap into the “Y” junction and call it “Neuter”, “N term”, Neutral”, it depends on the company. I rebuild them all over they years. Delco has a diode trio. It is 3 extra small diode who feed the regulator with voltage. This starts to fail, is where you get the dim red battery light on dash. When they changed to “CS” generation, they quit selling parts because they had 28 different regulators. It provides power to the coil at 400hZ instead of ground. And uses a “Delta” configured stator, which produces high current. The 194 “Peanut” shaped bulb got limits current to 0.25amp, same as test lights for years. Using this, you can connect to B+ and apply voltage on certain computer circuit without damage, because current in a series circuit is limited to the smallest resistor. I will check the book and let you know but don’t worry about stall and choke closing. It take 5/7 minute for the choke to cool down the bi-metal spring and tension the choke valve.

@@deankay4434 My main reason for wanting to wire it using the alternator as a trigger is so that the choke stops opening during a stall. I’ve had it stall on me while I was trying to let it warm up during extremely cold weather. Usually I’m away from it trying ti get the shed doors open while I let it run on fast idle to warm up. I’m not so much wanting to choke not to close, but rather stop opening for the few minutes it takes me to get it restarted in really cold weather. That said, it’s been pretty reliable outside of a failed carburetor gasket recently. Even more helpful would be keeping the choke powered and open for 5-10 minutes while at the fuel station in warm weather. Always a hard start when hot and the choke cools down while stopped for only a few minutes. But such is the way with a purely electric choke.

@@mebordernoneya8484 >Simply use a test light or volt- ohm meter meter to make sure your choke has voltage. My approach based upon your cold stall, is the choke is set to lean. Loosen the three screws and move one notch richer. This means to tighten the choke clockwise one notch. Snug screws and retry. I alway demanded carb rebuild spend the night to I could check the tension on the choke valve (Called Butterfly by Everyone) but going just one notch stiffer. Now, in a book or rebuild sheet will show the choke opening. This is not carved in stone, as all engine has characteristics. Now, if external, some have small hole to the out side as a bleeder. If you find a tiny hole, cover it with masking or duct tape. I use a hand held vacuum pump to open a cold choke valve. Measure at the top of the air horn and choke valve, changes when first started cold can be made leaner or richer. Simply pushing with a finger open or more closed, adjust the choke opener the direction that makes it run smoother. I do have to ask a painful question! Do you have a cotton-based air cleaner that looks cool and the box says it adds horse pony’s? If so, I can’t help you much. The reason the air filter is covered and had a snorkel with a heat riser tube (Foil cut to length heat riser tube) that the air cleaning draws warm/hot air into the air cleaner housing with a vacuum hose, now gone? Go find it for cold weather operation. The hose goes to live vacuum, bi-metal element, then to a housing with a valve that teeter-tooters to control air temp going into the carb. If cold, then engine runs betters when richer, this is why. The carb can not adjust the A/F ratio but controlling air temp between 140 degrees F to 148 degrees F ( Yours May Vary) but this is how they keep the engine running well when cold! So, choke setting, choke opening setting (Richer means smaller opening / leaner mean larger opening). Factory air cleaner vacuum hose, bi-metal valve and hot air vacuum motor (Diaphragm) opens when more heat is needed and drawn off the exhaust manifolds / headers (I guess if she’ll metal trap pulls hot air into air cleaner) keep air air correct temp. Remember, cold air is dense and contains more oxygen. Warm air is less dense and has less oxygen) Either warm or cold effects the air / fuel mixture. Too far one way or the other causes stumble/hesitation/falls flat on its face & stalls. The only thing you can do is more to where is the same temp all of the time. Adjust choke richer in winter, adjust leaner once warm outside. Install OEM air cleaner and adjust choke and opener to factory settings and remove the short hose with the bolts screwed into end, set to factory settings and eliminate stumble, hesitating or stalling. Pick one! Best, best of luck!

I hope you're still on YT. I have an '87 454 motorhome with an electric choke light in that never goes out. It reads around 14 volts at choke while engine's running only, so the choke is working correctly. My questions are why does the choke light stay on all of the time, and why am I getting 14 volts at the single choke wire, (which is fused at 20 amps in fuse box, and fuse is good)?

Yeah. I should do that. Still haven’t, though. LOL

Lol. Good job all the same.

Yes. Choke grounds through the carb body.

Tyler Thacker That should work fine. Any 12v circuit that comes on with the key will activate the relay and energize the choke like it should.

Should work just fine assuming that the linkages for the choke are all working correctly. Just use the pin out in the description and you should be fine. The wire with 3v is definitely not enough to operate a choke, but it may be adequate to run the relay. I would give it a try for the sake of convenience. Relays don’t take very much to run.

Never have had an electrical short. I’ve been lucky.

Trouble free installation for nearly 2 years so far. Thanks for commenting!

I’m not sure exactly what you mean. I have had it get flooded if that is what you are asking. That’s the downside to an electric choke. It can make it easy to flood them out on a hot restart. If you think it is flooded, just hold the pedal to the floor and crank until it clears. Holding the pedal to the floor forces the choke open to get more air through the carburetor.

Yes. Check the voltage at the electric choke. If you got it all right, the voltage will be the same as the voltage at the battery when the key is on, and will drop to zero when the key is off. You could also run an ammeter between the wire that feeds the choke and the electric connection choke. It should read zero with the key off, and should pull a couple of amps with the key on.

Some people get away with it. If you want to try it without a relay, pick a non-critical circuit to power the choke. The benefit to the relay is keeping the choke on a separate circuit so that there is no chance of overloading the factory wiring. The easiest key-on power source is the Ignition coil. If anything happens to the choke or the wiring to it, the fuse for the ignition pops and you are dead along side the road. The relay essentially eliminates that risk.

I didn’t measure the one I have installed, but typically speaking they are much less than an amp. Usually around 0.2 amps (200 milliamps).

@Bob Casteel > 3 watts if the coil is 90 ohms. Some relays have 60 ohm and others are close to 40. It is the amps the contacts can handle continuously that matters, but never measured a choke heater ever and be it is under 5amps. Use the Power solving math is P divided by I (amps) X E (voltage) Requires a direct readout amp clamp or a digital multimeter (DMM) but should be fused with correct size. DK, ASE master tech since 78

No. Power is always going to the relay, but the relay won’t send power to the choke until it sees power on the ignition coil. The relay acts as a switch for the Choke.

Ahh gotcha. So does the choke only operate when trying to start the vehicle? And after startup the choke starts to open back up slowly?

The choke will see 12 volts any time the ignition key is in the “run” position. That is to say, any time the ignition coil sees 12 volts the choke will as well. The only down side to this is if you turn your truck to “run” for any length of time before you try to start the truck, the choke will already be starting to open and it may start hard. For me though, this is a non issue. There is no reason to sit with the truck in “run” without starting it.

So you’re saying the choke will be applied at all times. If the truck is running, the choke in on. Key turned to acc, choke will be on. I only want to choke to be on for a couple minutes until the truck warms up. No need for the choke to be on if you’ve been driving for 30 mins. Any ideas?

An Electric Choke begins to open when it sees 12 volts. When the 12 volt signal goes away it begins to close as the element in the choke cools off. So, hooked up as I have above, when the key is off, the choke will begin to close until it is fully closed. i When the key is on the choke will begin to open until it is fully open. If you wire it the way I (tried to) describe, it will work the way it should. The choke will be closed at start up and will start to open as soon as the key is switched to “run”. So as the engine runs and warms up, the choke warms up and begins to open. Wire it like I did and you will be happy. IMO.

Yeah, it was leaking. Upper hose relaxed and was seeping. Gave the clamp a couple cranks and It’s fixed now.