Quadrajet choke

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Old May 8, 2014 | 10:26 AM
  #1  
wcourt3010's Avatar
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Quadrajet choke

Hi, i'm putting a 3711 (eddie performer) intake on my 350. Going to go back to the Rochester 4 bbl that came with the car and want to get it rebuilt.

I believe the choke on that was hooked up to the intake, it wasn't electric and wasn't manual (had it off for so long, can't really remember). Should I stick with that and hook it back up to the 3711 or should i get an electric choke installed while i get it rebuilt if that's even possible? Really don't want a manual with a cable running through the firewall.

My engine was a 73-76 but i put 7a heads on it. I'm assuming the carb belongs to that original intake. I don;t know the number on it but could find out.


cheers
Warren
Old May 8, 2014 | 11:39 AM
  #2  
hookem horns's Avatar
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Electric choke is an easy swap on a 70+ carb with the choke coil on the side of the carb.
Old May 8, 2014 | 11:53 AM
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Your original choke is a hot air choke. It used air heated in the exhaust crossover to warm the bimetallic spring in the round choke housing, which opened the choke plate. An electric choke uses the same bimetallic spring but heats it with an electric heater. Simply remove the three screws that retain the black plastic choke coil cover, swap your existing coil for an electric one (I use the coil from a mid-1980s Chevy pickup with 454 and Qjet), and wire it as described in this thread.
Old May 8, 2014 | 12:15 PM
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Just a follow up question, I swapped the choke on my 2GC to electric but the coil doesn't seem to be heating up. I verified that it is getting 12v to the spade connector and their is continuity between the connector and the coil.

Should the coil tighten up or unwind when heated?
Old May 8, 2014 | 12:20 PM
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wcourt3010's Avatar
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Thanks, Joe and the other responders.
Old May 8, 2014 | 12:28 PM
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Originally Posted by 72cuttys
Just a follow up question, I swapped the choke on my 2GC to electric but the coil doesn't seem to be heating up. I verified that it is getting 12v to the spade connector and their is continuity between the connector and the coil.

Should the coil tighten up or unwind when heated?
The coil expands when heated, so I guess you'd call that "unwind". It's very easy to test your coil. Take it off the carb, connect the terminal to +12V, ground the metal disk, and look at it. It might help to make a mark indicating the location of the coil when cold before starting.

Be aware that GM used coils wound in both directions, depending on application. Typically (but not always) the 2GC choke requires the coil to be opposite that for a Qjet.
Old May 8, 2014 | 12:39 PM
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Speaking of Quadrajet chokes, can somebody tell me why I have to manually "kick off" the choke to get to lower idle? It's like the choke pull off isn't working or something. After the car warms up a little, I have to open the hood, feel around under the air cleaner, and hit that switch. It then drops down to regular idle. I have searched forums on it, some have said, "soak it with PB blaster, wd-40, something like that". It works briefly, then back to popping the hood, and kicking the thing off manually again. Hope this makes sense, and any input is more than welcome. Thanks.


PS- it's an electric choke btw.
Old May 8, 2014 | 01:09 PM
  #8  
joe_padavano's Avatar
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Originally Posted by kevin.horton
Speaking of Quadrajet chokes, can somebody tell me why I have to manually "kick off" the choke to get to lower idle? It's like the choke pull off isn't working or something. After the car warms up a little, I have to open the hood, feel around under the air cleaner, and hit that switch. It then drops down to regular idle. I have searched forums on it, some have said, "soak it with PB blaster, wd-40, something like that". It works briefly, then back to popping the hood, and kicking the thing off manually again. Hope this makes sense, and any input is more than welcome. Thanks.


PS- it's an electric choke btw.
The electric choke doesn't matter, it's still a bimetallic coil. If you are saying that you need to jab the throttle to knock the carb off of fast idle, that's normal. If you are saying that even after doing that, you need to actually move the fast idle cam to the choke-off position, then there could be one of two problems. Either the choke coil isn't properly moving the fast idle cam (due either to misadjustment or a coil that's lost spring tension) or more likely the fast idle cam is sticking due to crud. You don't want to use lubrication on the carb linkage because that just attracts more dirt, which eventually makes it worse. More likely you will need to disassemble and clean the choke and fast idle cam, checking the surfaces where the fast idle cam rotates on the linkage shaft. The cam should rotate easily under gravity force if the primary throttle shaft is held open and the choke is warmed up. If it doesn't, figure out why.
Old May 8, 2014 | 01:36 PM
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Originally Posted by joe_padavano
The electric choke doesn't matter, it's still a bimetallic coil. If you are saying that you need to jab the throttle to knock the carb off of fast idle, that's normal. If you are saying that even after doing that, you need to actually move the fast idle cam to the choke-off position, then there could be one of two problems. Either the choke coil isn't properly moving the fast idle cam (due either to misadjustment or a coil that's lost spring tension) or more likely the fast idle cam is sticking due to crud. You don't want to use lubrication on the carb linkage because that just attracts more dirt, which eventually makes it worse. More likely you will need to disassemble and clean the choke and fast idle cam, checking the surfaces where the fast idle cam rotates on the linkage shaft. The cam should rotate easily under gravity force if the primary throttle shaft is held open and the choke is warmed up. If it doesn't, figure out why.

Joe, yeah, thank you. I have tried kicking the throttle to kick the idle down, and it just doesn't do it. I guess I need to take the choke and fast idle cam off and clean them?
Old May 8, 2014 | 02:21 PM
  #10  
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Originally Posted by kevin.horton
Joe, yeah, thank you. I have tried kicking the throttle to kick the idle down, and it just doesn't do it. I guess I need to take the choke and fast idle cam off and clean them?
Assuming your choke coil is working properly, yeah, take them off and clean them. Check the bore on the cam and the shaft that it rides on for scoring or corrosion. Clean up anything you find. The cam should pivot freely with no lube.
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