'70 C10 thermostatic divorced choke linkage help

[82crawler]

1970 C10, 350ci motor. As far as I know, the intake and carb are stock with divorced thermostatic choke. Have had carb trouble for the past year. Rebuilt the carb 9 months ago, the truck has been running much better since, but still has issues. Divorced choke is my main concern at the moment, doesn't really seem to be working properly. Currently have the carb on the bench to investigate.

This is the current choke setup. I think I have that tiny spring in the wrong place, the one poking through the slot in the vacuum brake. In the original takedown (further below), that spring is doing absolutely nothing at all, resting on the choke lever on each side of the spring. What's the purpose of that little spring? It seems like the choke lever should be free-moving, because the thermostatic choke spring isn't very powerful (I have a brand new one installed).

Current setup:


Original (since previous-owner rebuild) setup:


Lastly, where is the fast idle cam supposed to rest? On top of or below the arm of the choke lever? Right now, it's below. I don't know the stock configuration.




Sorry for the confusing questions and pictures.

[geezer#99]

That spring is hooked in the right spot. It's used to pull back the lever on the vac pot when the vacuum drops when you open the throttle to kick open the secondaries.
You might need to wind it once more around the shaft to tighten it up a bit.
Look in this link. You'll see it's hooked right.
https://www.corvetteforum.com/forums...djustment.html

[82crawler]

Interesting. It's not shown in those photos, but do I have the bottom end of the spring in the right hole? If it pulls on the vacuum brake, should it still be affecting the choke lever? Or should I have the bottom end of it through the fixed plate instead of the choke lever. Right now it's constantly pushing the choke lever down (full choke), and therefore fighting the thermo choke coil which wants to push up while heating, causing the 2 to cancel out.


From looking at your link, and my old pictures, I appear to have the vacuum brake rod flipped backwards, although I'm not sure how much difference it makes.

I also think I have the fast idle cam on the wrong (lower) side of the choke lever. If it were sitting above the choke lever, then the choke would pull up on the fast idle cam under choke (duh). I think that makes sense?

[geezer#99]

Consult your manual!!
You do have one, right!!
Like this.
http://cliffshighperformance.com/Qua...et-carburetors

Also if you look on the link, Cliff has a forum you can join and get expert advice from.

[demian5]

Where is the lever that keeps the secondaries from opening until the choke is off?

[82crawler]

I don't have a Quadrajet specific manual. My Haynes manual doesn't mention or picture my specific style of choke.

I removed that choke/secondary lever, per the advice of a youtube series on Qjet rebuilds by WhoSaidTyler. If it's on the internet, it must be true, right?!

[82crawler]

For anyone curious, I found the culprit to be the retaining clip on the choke rod, holding it to the carb linkage. The hole in the retaining clip at the top is so small that it was binding the choke rod and preventing it from rotating as the rod moved up and down. So wherever I set the choke linkage is where it would stay. Ended up grinding some notches in the rod and wrapping a small cotter pin around it. Need to find a little E-clip like the ones used on the rest of the carb.

[54blackhornet]

Glad you found the culprit ! FYI you can buy a electric choke conversion to eliminate the manifold bi metallic spring housing. Mounts to manifold in stock location.....

[82crawler]

I've wondered about that. Which part of it is electric? What powers it? I almost don't want to switch, now that I've fiddled with this thing SO much and finally understand it completely, and got it working correctly! Not to mention all of my bi-metal choke parts are now brand new.