Quadrajet choke adjustment questions

[CactusCurt]

Ok, more detail to be added later but here's the skinny.

The electric choke on my Qjet on my stroker never worked right , so it was disabled. Rig is only used in the summer, so not that big a deal but on the fix-it list and currently underway. The carb is from Jet and is basically new.

So after putting it on the bench and pulling the choke housing and linkage and putting it back together the way I *think* it goes, this is where I'm at.

To cold start, she won't close the choke blade by moving the throttle until I adjust the choke blade. So turn the choke adjustment dial (black bakelite dial in choke housing)to snug closed but not tight. Starts like a champ, choke pull-off appears to be functioning and adjusted correctly.

BUT, after running on high idle for plenty long (10 minutes), the bi-metal coil hasn't opened the choke blade all the way to the point it falls off the high idle adjustment. During this process I end up having to tinker with the high idle speed, whose adjustment mechanism seems to be working as intended.

If I push down on the high idle cam with my finger, I can feel ever so slight pressure (spring?) wanting to push it back up. However, I can't "release" it with my finger, so I have to go back to the choke adjustment and open it (15 or 20 degrees of rotation?) until it falls off the high idle adjustment and onto the curb idle adjustment. I can bang on the throttle all I want (clear to WOT), but that doesnt kick it off the high idle either. I can't figure out what's keeping the fast idle cam from falling.

I will go out when it warms up and go thru the process again detailing the gymnastics i have to go thru - including pictures! I'm getting pretty good at it.

This thing runs PERFECT except for the choke. I don't want to have to replace it with some junk edelbrock or TBi.

If you can walk me thru this, I will send you a box of beer cans.

[Truckman]

Mind you it's only been 23 years + since I worked on one of these and my memory comes and goes at times...So, is the heat tube from the heat riser valve intact from the exhaust manifold to the choke heater, and are there any kinks or rust pockets in it?...Are you getting actual heat all the way to the coil inside the bakelite housing?...Is the coil reacting as it should to the presence of heat?...If not, is the heat riser valve working, or is it always closed?...Do you have either headers or an intake manifold that does not permit exhaust heat to cross from one bank to the other?...Check all that and get back to us......Ben

[CactusCurt]

Electric choke.....not divorced or exhaust heat activated. Yes, bi-metal coil is causing choke plate to open as intended - but not far enough?

Only thing I won't be able to get is vacuum reading, but that shouldn't matter? No leaks, she's pretty clean. Like I said runs perfect when I manipulate the choke manually.

It's just like the high idle cam is ever so slightly being held by something that's not allowing it to drop. It seemed to work perfect on the bench and I don't have any linkage interference that I can find. It's almost like I don't have the range of motion I need in the bi-metal spring.

When it gets up to around 32 degrees in a couple of hours I will go back out and monkey with it. I apologize in advance for the PTSD remembering qjet diagrams is certain to cause.

Here's a overall pic to give you a feel for what we are looking at. You don't need to wash your hands after working on it Detail to follow.

[Truckman]

Here's a overall pic to give you a feel for what we are looking at.

Looks like headers, correct?...Is there any crossover heat?......Ben

[CactusCurt]

Looks like headers, correct?...Is there any crossover heat?......Ben

Yes headers, but no "heat riser" into choke housing, the movement in the bi-metal coil spring is all created by a switched 12v connection. Once the key is turned on, the coil holds the choke plates open as long as the key is on and electricity flows to the coil. Ground is thru the carb body. Much cleaner than the nasty exhaust operated one - and you don't get fouled up with that tiny vacuum orifice. All of that stuff appears to be functioning.

I believe this is what we could call a modern q-jet.

[Truckman]

Once the key is turned on, the coil holds the choke plates open as long as the key is on and electricity flows to the coil.

I understand that part, but I take it with headers you don't have one exhaust bank closed with (I forget what that valve was called) to send exhaust heat through a crossover passage in the intake manifold to heat it...I think the choke/high idle discrepancy will just be a matter of adjustment...Maybe Mastertech will see this and stop in......Ben