307 HO Choke question. Electric upgrade? Will not kick off high idle

[oxide80]

Having a little issue with the choke on my 87 442, right now chasing down a few small vacuum leaks from aged and cracked vacuum lines, but I noticed my choke doesn't like to kick all the way down, usually goes to half choke and stays there until you tap the choke pull off with your finger, It has the stock CCC Q-Jet. Is it worth upgrading to an electric choke from the factory thermo tubes? I noticed Jet offers a conversion kit for around $40, but will the electric choke off a MC SS be the same? Rock Auto has those for around $20... Im going to check the choke pull off and replace if its leaking by. any other suggestions or recommendations?

Thanks

 

[pontiacgp]

your hot air choke is better than the electric choke. The hot air system works according to conditions and isn't just a timed choke.

 

[Bonnewagon]

All I use is an electric choke. Get the electric choke coil as cheap as you can, they are pretty much all the same. Then you remove the thin gasket on the choke housing because you need good electrical contact between the coil and the carb body. Then you need to remove the plastic vacuum tube that goes between the choke housing and the carb body. Then plug the vacuum hole in the carb body or it becomes a tiny vacuum leak. Just get a bit of fishing sinker lead and tap it into the hole in the carb body. GM used a stupid grey plastic clip to connect the choke wire to the choke coil. It rusts and makes poor contact and it also breaks for the slightest excuse. I prefer to solder a wire to the choke coil tab, then connect that wire to a bullet connector, and then that to a switched ignition source. GM used an oil pressure switch to run the choke only when it saw oil pressure but you can do without that. Just don't leave the ignition on without the motor running for a long time. ,

 

[airboatgreg]

I agree with bonnewagon if you convert. I am ok with a choke stove set up but... you have to have vacuum. The stove has to be clear to the air intake at the top rear of carb. Choke system has to be free. Rubber seal in choke housing has to be good. Choke pull offs have to work. Fast idle set properly. Round gasket around t-stat spring housing good. And you could just have a worn choke thermostat. Don't forget the hot air induction off of the exhaust manifold as the idle ports in carb may ice up and create a stall condition. I agree with the previous advice on the choke stove being more realistic to cold weather drivability.

 

[Quadrajet Power]

Lots of cars have clogged heat passages from age and hot air choke doesn't work like they should. They are good if they have proper heat source.
I have great quality choke coils in my store.
https://www.quadrajetpower.com/online-store/Electric-Choke-Coil-Flat-terminal-New-p71873538

 

[olds307 and 403]

You probably need a new hot air choke coil, they go bad to or it is out of adjustment. Either replace the hot air coil or add an electric choke coil, the gasket behind the coil must be removed with electric.

 

[MrSony]

First, before you buy anything, try and fix it yourself. Could just be sticky linkage. Procedure to set the choke on a qjet is as follows: With the motor STONE COLD, over night cold, remove the air cleaner and locate the philips/flathead screw under the choke thermostat housing on the passenger side. Check if the choke flap is closed, if not, close it. When closed the grey and green tabs behind the choke thermostat housing should both be upright. back the screw under the housing out a couple turns, then back out the curb idle screw on the drivers side. This is to be done with the car off mind you. Confirm the throttle is fully 100% closed. Open the throttle a bit, and the grey and green tabs should flop down. Hold the throttle open a little, push the tabs up to vertical, and turn the philips/flathead screw about 2 turns to get you started. As you turn it, watch the drivers side linkage start to move. This is the fast idle working off the larger of the two steps on the choke linkage. Now, plug any vacuum lines and go start the car. It should start if your car and carb are in working order. Watch the carb and see what the choke flap does until the car gets upto operating temp. When it does, then you set your curb idle on the driver's side to idle where you want it to. When all said and done, when the engine is cold and not running, you should be able to set the choke by pressing once on the gas all the way to the floor, a quick jab, (or just whack the throttle linkage open and see if the choke flap closes), and then start the engine. The choke pulloff will pull the choke open about 1/4 of an inch or so to allow it to breath after that initial shot of fuel it gave when you set the choke instead of drowning itself. Then once the car is idleing, it should idle at anywhere from 1100 to 1400rpm when stone cold, and 800-900 when warm in park. You should be able to override the choke whenever you want by lightly jabbing the pedal to get the choke to come off and open fully, such as when it's 80 degrees out and it's only been sitting over night so it's not ice cold.


Phew, that was a lot of words wasn't it?

 

[MrSony]

If that doesn't help it, just convert to electric choke as mentioned. You could just nab the wire and coil off any ol qjet (avoid the ones with rivets. Stupid GM) at a junkyard, or an unsuspecting friends ride. Remove the gasket, put it to a 12v switched source that is only active when the key is on IGN, or the car is running. Some tap into the wiper controls, some the alternator field wire (alternator spins=power. no spin [engine off] no power), or buy the little sender that screws into the block for oil pressure with two tangs on it. One for the gauge/idiot light/whatever you have, and one for the choke. No oil pressure, no choke.

 

[DoubleV]

Converting to electric choke offers zero benefit. Not worth it at all. I converted to electric because my intake didn't have provision for hot air setup.

 

[olds307 and 403]

Lots of cars have clogged heat passages from age and hot air choke doesn't work like they should. They are good if they have proper heat source.
I have great quality choke coils in my store.
https://www.quadrajetpower.com/online-store/Electric-Choke-Coil-Flat-terminal-New-p71873538

I have actually seen the tubes rusted through in the intake as well. The hot air choke is better than I gave it credit for, depends on how original your car is as well.