Q-jet electric choke question

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CutlassKage

Not-quite-so-new-guy
Dec 19, 2016
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Mutant, after playing around, I don't think the choke is working properly. Btw: it's a 2jet so not sure why I originally wrote q. Anyways, it does not look like the original carb and was probably changed to electric choke. Choke is pretty open upon cold with very little play and does not seem much different when warmed up. Two vacuum ports in back of stock air cleaner are open and doesn't look like there is anywhere to go. Thoughts? Appreciate all the support.
 

MrSony

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Nov 15, 2014
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Mutant, after playing around, I don't think the choke is working properly. Btw: it's a 2jet so not sure why I originally wrote q. Anyways, it does not look like the original carb and was probably changed to electric choke. Choke is pretty open upon cold with very little play and does not seem much different when warmed up. Two vacuum ports in back of stock air cleaner are open and doesn't look like there is anywhere to go. Thoughts? Appreciate all the support.
Have you watched the carb as the car warms up? Take the air cleaner off, plug all lines, an start it. Engine has to be overnight cold. Could be a bad choke coil. What engine is it?
 

foxtrot

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Dec 19, 2008
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Mutant, after playing around, I don't think the choke is working properly. Btw: it's a 2jet so not sure why I originally wrote q. Anyways, it does not look like the original carb and was probably changed to electric choke. Choke is pretty open upon cold with very little play and does not seem much different when warmed up. Two vacuum ports in back of stock air cleaner are open and doesn't look like there is anywhere to go. Thoughts? Appreciate all the support.
I agree that it sounds like the choke isn't adjusted properly. I would adjust this first and then check the EFE for proper operation. As MrSony mentioned, when the ignition is turned off (cold) and the accelerator peddle is depressed fully the choke flap should close.
 

Bonnewagon

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Mr Sony is getting to be a Q-jet guy! Well done! Anyway- as stated above- be sure the choke is totally closed at cold start up. That is adjusted by turning the black housing. Upon start up the motor will fast idle like what Mr Sony said and that is adjusted by the screw under the choke linkage. The vacuum pull-off will open the choke flap a specified amount. That is where it gets tricky. There used to be specs for the measurement of the opening but then GM went to a stupid angle gauge that no one owns. Rule of thumb is about 1/8" to 1/4" measured with a drill bit. It is adjusted by turning the philips head screw on the pull-off with the motor off. You use a Mighty-Vac or other vacuum source to open the flap and measure. If upon start-up the motor stumbles and coughs- the flap gap is too small and it is running too rich. If the motor dies- the flap gap is too big and motor is dying from leanness. All adjustments MUST be made on a cold motor. A properly adjusted choke will run perfect no matter what the ambient temperature is. If the choke never opens- look for power at the choke coil. The connector gets rusty and fails.
 
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CutlassKage

Not-quite-so-new-guy
Dec 19, 2016
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Thanks guys. Flap is open and I think that's the problem. Well open when cold with little movement when hot. Flap has no spring when you push down on it. Will try adjustment and go from there.
 

airboatgreg

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Oct 2, 2016
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Rule of thumb is the choke plate should just close at about 75 degrees and maybe 2 notches richer. Due to fuels being formulated for fuel injection cold drivability can be an issue. Do 2 -3 good pumps of fuel on a cold start and take foot of pedal. Should start on fast idle, let run a bit, tap accelerator, should lower idle and drive off. If stalls or hesitates 1/2- 1 mile away look at hot air intake in snorkel. Carb can ice up in higher humidity and moderate temperatures. If higher mileage may have carbon build-up in intake and runners and that acts a sponge and fuel never gets to combustion chamber. Can elaborate more if needed
 

MrSony

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Choke flap should have a nice springy snap shut when you push it open on a cold motor. You can see how the pull off works by pushing in on the little arm, use that to check the gap on the choke flap. Measure from the back of the choke opening to the edge of the flap. Use a drill bit as stated above for accurate measurement. When the engine is at temp, if the flap seems limp but is open (and the fast idle cam [silver weight, called an elephant ear often, and the green thing are horizontal, indicating the choke is off), the coil could be bad or not getting 12v to the wire. Switched ignition, only should get 12v one car is on or on the start position, nothing else. Some tee into the alternator field wire (commonly the brown one off the back of it), or the wiper motor wire which is yellow(?). GM teed into the oil pressure sender with a green wire(?). No oil pressure, no choke. Easy way to adjust fast idle is on a STONE COLD MOTOR (see a theme here?), back out the adjustment screw all the way until it starts to get loose, don't lose it! Crack the throttle a TEENY bit, hold the fast idle cams upright, and tighten the screw. Watch carefully and you'll see the throttle shaft start to move as if it's being opened, that's what the fast idle does. But automatically. Go from there. If it idles too high after about 30 seconds, (really you should get a tachometer or a nice timing light with one built in to check accurately), shut it off immediately. Wait an hour or so, and try again in small increments. You only have about a 20 minute window before the engine starts to warm up if it's above freezing.
 
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Canon_Mutant

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Damn it, Jim . . . [Bones to Kirk!]

I was all prepared to write up impressive detail tonight on how I set mine up with related intricacies and you beat me to it.

Well written Mr Sony . . .
xigKrAa4T.gif
 
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CutlassKage

Not-quite-so-new-guy
Dec 19, 2016
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Thanks everyone. Pictured is my carb when cold. I tried to adjust choke and flap doesn't even budge. Haven't driven this much since I got in it December. Drove it 3 hours home but still had start stall when cold. Any thoughts of what to replace or rebuild? I have a few rochesters so could just fully replace.
 

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CutlassKage

Not-quite-so-new-guy
Dec 19, 2016
34
3
8
All, looks like the flap was stuck. Reset everything and it started right up...idled and drove fine. I put on the carb cleaner and later some oil on outside linkage. When I can home from work, flap did not close and still stuck. I assumed electricity choke was working as the flap opened up while engine getting warm. Any thoughts?
 
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