Carb Problem

[stepsider]

!972 Stepside 350 ci & 350 tranny. Had the Carb rebuilt because the choke was not working, was zip tied open, Don't know why. Carb check out as a 72 Q jet 4 Barrel. Replaced the choke spring from Napa. $ 49.00 dollars !! Now the problem,

Car starts & runs but the kick down doesn't work. Run for ever at a fast idle until I move it by hand off the fast idle cam. I'm guessing that why the had it zip tied open. I should be able to set the fast idle when cold with the gas pedal & should be able to kick down the idle wi a tap of the pedal. They told me my model carb won't accept a aftermarket electric conversion ?? Need Some advice or answers.

[truckster]

Can you post a picture of the carb? I suspect your linkages aren't set up correctly.

[Getter-Done]

Pictures for the forum will help

And This book would help (For Sure).

Link : https://cliffshighperformance.com/pr...et-carburetors

[oldgold70c10]

On a q-jet, the choke flap opens gradually as the bimetallic spring heats up from engine heat or from an electric heater in the case of electric chokes. The fast idle cam is not spring loaded, but instead has an arm that is weighted slightly on the end. The fast idle cam will stay on the high step until you tap the accelerator pedal so the arm can fall down and strike the choke lever that it follows.

Check the fast idle cam and the point where it pivots and make sure it is free enough to fall down by its own weight. Sometimes when they stick only slightly the first few bumps you drive over will cause it to fall down to the normal idle position, but for it to fall when idling in the driveway, it has to be moving freely. Also make sure you put the fast idle cam on the correct side of the choke lever. It should be situated where the choke lever forces it up when going to the closed position, but the choke lever can go back to the open position without the fast idle cam following.

[geezer#99]

Since you can move it off the fast idle by hand says the linkages are good.
You just need to adjust the linkage rod from the coil to the carb leaner.
There’s a post here from Joe Podavano with a good illustration for you.


https://forums.aaca.org/topic/355944...966-chevy-396/

They are correct about an electric choke conversion that is mounted on your carb won’t work on yours. There is a stand alone electric choke that bolts to the intake though.
Like here.



https://quadrajetparts.com/electroni...971-p-399.html

Your linkage rod length can be effected by your carb base gasket. That could be the cause of your choke being wired open.

[HO455]

I've seen lots of chokes assembled incorrectly or modified by well-meaning folks who thought they were fixing things. Look closely your carbs linkages and how they work together. The various parts should all move freely.
This link may help. It is about the carburetor on my Burban, it's not the exact carburetor as yours but it may help you. See post 618. For the electric choke installation go to post 590 on the previous page.

https://67-72chevytrucks.com/vboard/...698377&page=25