Quadrajet question

[bob8619]

I've never worked on a QJet before and its been years since I've worked on any carb so I'm a bit stumped right now.

So when I press the gas pedal it pulls the throttle lever on the drivers side of the carb, this also simultaneously flips the linkage on the passenger side (as seen in the pic) which closes the choke plate. From what I can tell, something should be on the passenger side that eventually pushes that linkage back the opposite way which opens the choke plates and prevents it from being pushed again when gas pedal is pushed.

I live in Florida and don't really need a choke so I figured I'll just remove the choke plate and call it a day but it turns out it still goes into a high idle setting when that linkage on the passenger side is flipped (by pressing the gas pedal).

Does it look like something is missing? Can I just rig that linkage to remain in the position to not let it get flipped when I press the gas or does it have to do with something other than cold starting?



This is a 68 C10 but it has a 305 in it from 76-79 range. Just bought it as a project truck so its all set up how the previous owner had it.

[B. W.]

You can wire the choke open, won't have a choke (obviously!)
Looks like your secondary lock out is missing also
Should look something like this:

[bob8619]

So that linkage that I talk about that flips on the passenger side when I press the gas is only related to choke and theres no harm in using some wire to manually keep it in the no choke postion? Other than the fact that I wont have choke obviously.

And is the secondary lock out the piece that I circled in your picture? I'm assuming I should replace it?

[geezer#99]

Some carbs never had that style lock out. Leave it alone if you’ve never had one apart.
Just remember to let the motor warm up before you put pedal to the metal.
And yes you can tie that linkage downward using the hole the choke rod is clipped into.
Your carb isn’t a match for your intake.
Your carb is a divorced choke, your intake is for an electric choke style carb.

[Richard2112]

I have just finished a complete overhaul on my Rochester carb and it works nicely. No modification except to use manual choke instead of divorced.

You would be better suited to fix whatever is wrong with your carb than to remove the choke plate. I understand that you may live in a warm climate so cold starts don't seem like a problem but "cold" is relative.

What seems warm to you is actually "cold" to your carburetor and your carb must warm up to operate properly. Warm up relative to your engine operating temp, that is.

Your choke plate does more than meets the eye under 'cold" conditions. Your carb does not emulsify the F/A mix very well when first started so the choke plate acts as a restriction, decreasing volume, increasing the velocity of the mix and enriching the F/A on the idle circuit.



Without the choke plate, though you may be able to start and run your vehicle, your mixture would have to be set to run off ratio, that is, too rich for optimum performance.

That other thing you're referring to is your fast idle cam which works in conjunction with your choke plate and when set properly, works very well.

From what I can tell, something should be on the passenger side that eventually pushes that linkage back the opposite way which opens the choke plates and prevents it from being pushed again when gas pedal is pushed

There is something that "pushes that linkage back the opposite way" but it does not happen when you push the gas pedal. That something is the vacuum pot and it's called the choke pull-off. It (if operating correctly) will open the choke (on a Rochester) about 1/4 to 5/16 inch when it tries to start and pulls sufficient vacuum to run. Check to see of your is operating correctly. Disconnect the hose from the vac pot, push the linkage into it and hold your finger over the port. Release the linkage and it shouldn't move from it position. If it does, it's leaking. Put a new one on.

[bob8619]

But when I push that choke pull off in, as if the vacuum were pulling on it, it doesn't revert that other linkage back to the non choke setting. Are you saying that that arm that retracts inside the pull off should actually be pulling that linkage back?

[Richard2112]

Originally Posted by bob8619

But when I push that choke pull off in, as if the vacuum were pulling on it, it doesn't revert that other linkage back to the non choke setting. Are you saying that that arm that retracts inside the pull off should actually be pulling that linkage back?

The linkage that goes into the choke pull off should open the choke plate a small amount, usually 1/4 to 5/16. It is vacuum operated but you should be able to operate it by hand and cause the choke plate to open slightly.

[geezer#99]

Originally Posted by bob8619

But when I push that choke pull off in, as if the vacuum were pulling on it, it doesn't revert that other linkage back to the non choke setting. Are you saying that that arm that retracts inside the pull off should actually be pulling that linkage back?

Richard is right. The vacpot only pulls the choke plate open.

In post #3 you’ve partly circled that vertical rod that goes into the shiny choke stove on the intake. The top of the rod hooks into that slotted hole on the carb. If you hold the throttle open about halfway you can pull down or push up on that slotted hole arm and the choke plate will either close all the way or open all the way. I can’t remember which way but just try it yourself.
When you find which direction to move it then you’ll know which way to tie it open. You’ll still need the choke pot working as it acts as a dampener for the secondary air door. The linkage for that is the long rod.