[Baba O'Riley]

Car is '71 Formula 400, with a just-rebuilt Rochester 7041263 and one of those “divorced choke thermostat” setups with the flat coiled spring.

I'm having problems with cold starts, it runs weak and rough at first with very heavy gas fumes. Sometimes the car only starts cold with the pedal floored – and a big bolt jammed in the choke butterfly so it’s all the way open.

Question -- the spiral spring on the choke thermostat, on a 7041263 -- does the looped end of the spring that attaches to the rod face the FRONT of the car, or the BACK? At present it's front-facing.

Just trying to make sure it's on right and eliminate this as a source of the trouble.

Thanks as always for your expertise.

[3tas4me]

I don’t think it faces either. The end of the choke coil where the rod attaches should be at the carb end. Sounds more like you have a choke rod adjustment to make or a problem with the pull off.

[dataway]

Far as I know, and on my car, the coil loop end faces the carb, and has a rod with a 90 degree bend that slides into the loop, the rod comes out of the choke stove towards the front of the engine.

But now that I think about it, I'm not sure if mine is right either.

Is this correct? (But in my case it's a 68)

[Formulabruce]

Baba, seems like you are Way to choked for your temperature. When all set up you should EASILY be able to push open choke flap on top of carb. In Santa Monica, That flap shouldn't even be fully closed.. If new repop spring, you can and should shorten the rid that comes out of it where the bend is. This is the way they are adjusted if all hooked up "Correctly " .
I have seen a couple that the rebuilders installed the " inside the carb" choke linkage rod on backwards. This can cause issues as well. Good luck!

[jhein]

Here's a decent video on choke rod operation and adjustment.

https://youtu.be/bzg56YS4z94?si=kAGjUicoQ1tXdXjX

[unruhjonny]

beware(!)
The 2bbl choke thermostats are coiled opposite of the 4bbl choke thermostats - but look otherwise identical.

I also believe that the 1971/1972 choke rods do not have the bent to allow for adjustment as the earlier ones do.

[jhein]

Originally Posted by Baba O'Riley

Car is '71 Formula 400, with a just-rebuilt Rochester 7041263 and one of those “divorced choke thermostat” setups with the flat coiled spring.

I'm having problems with cold starts, it runs weak and rough at first with very heavy gas fumes. Sometimes the car only starts cold with the pedal floored – and a big bolt jammed in the choke butterfly so it’s all the way open.

Question -- the spiral spring on the choke thermostat, on a 7041263 -- does the looped end of the spring that attaches to the rod face the FRONT of the car, or the BACK? At present it's front-facing.

Just trying to make sure it's on right and eliminate this as a source of the trouble.

Thanks as always for your expertise.

So re-reading the OP, there are a couple things. The heavy gas fumes and the fact that you need to hold the accelerator wide open to start (like a flooded motor) would seem to suggest it's flooded. Also the fact that you have to prop open the choke valve would seem to indicate the same thing. That's letting in a lot more air and no fuel from the main metering system, leaning the whole thing out. I don't know enough about Qjets to know where to go from there but it seems like you have way too much fuel at startup and idle. So maybe has little to do with your choke operation? I'm sure someone who knows more will chime in soon.

[unruhjonny]

I have found that if the Quadrajet is set up right, you should be able to fully disconnect the choke coil, and start it - just be sure the primary/choke top butterfly is nearly closed.

If you are able to get it started fairly easily with the choke coil disconnected, and the problem is really only when that coil is connected, then you have something askew;
Verify that you have the correct coil - and that it's pulling the choke to nearly closed when you hit the gas pre-starting.

That video was a Buick(?) Quadarjet, and it mentions that the BB Chev have a coil that goes the opposite way;
With our Pointacs, the 2bbl and 4bbl coils work the opposite way.

[Baba O'Riley]

Okay, the choke that's been on it as long as I've had it (30 years) has sat lateral / parallel lengthwise to the carb, with the spring's end loop for the choke rod connect facing front. But -- then I looked online at pics of various Rochester choke setups and yes, some of them sit sideways like in Dataway's pic, not fore/aft like mine has been running, correctly or otherwise.

On mine, which was California-built and originally sold in LA, FWIW:

The choke assembly has at its base a bolt hole on one side and a small cylindrical pin on the other. The manifold, the original 481733, has two holes about 1-1/8" apart. The inside (closest to carb) hole is slightly larger, unthreaded, and fits the pin at the base of the choke coil assembly; the outside hole is threaded and that lines up with the bolt hole on the choke. I tried to find a way for it to fit sideways and couldn't, so I think this is how it's supposed to go.

I bought a replacement choke that is too small to fit these holes, but the spring tension in the new choke is similar to the existing unit so I don't think a tired coil spring is a factor.

F-Bruce -- yes, I think you're right about the over-choke. Wondering if that's causing those gas fumes on cold startups. The choke flap isn't moving that easily.

Does anyone have pics of the right way that the choke linkage rod is supposed to install on these?

[gto4ben]

I recently set up my choke for my 7041262 quadrajet which is the automatic version of your carb. For non HO carbs, the rod is left stock. This corresponds to a length that fits the rich slot when fully closed. For HO carbs, the rod is bent to fit the center slot.

[unruhjonny]

the choke coils are model year, and engine family specific.

even though there are different part numbers for the 1967-1970 coils, from what I have seen, they should all interchange - but I suspect the part numbers indicate operation specific to that application.

The 71-72 choke coils are different from the earlier ones.

This is key:

the spring's end loop for the choke rod connect facing front.

Sounds like you have the correct one.

The attached images show 71-72 coils on the left side;
The 2bbl coils have the rod connector on the coil at the left side, while the 4bbl have it on the right;
All (excpet the 71-HO?) 71-72 Pontiac coils use the same cover.

EDIT:
It looks like I replaced the covers backwards after taking the picture with the covers off for you - I'll need to correct that!

[Baba O'Riley]

GTO4Ben -- that's very close to what mine looks like. Let me do a refresher on posting pics on here and I'll show y'all.

[Baba O'Riley]

https://photos.app.goo.gl/ffHiF6scZKhdfX8m7

https://photos.app.goo.gl/weVr1CQPe7sa5uNW6

[Baba O'Riley]

Sorry -- I am hitting the Insert Image button then pasting the links to reduced-size pics I've uploaded to Google Photos, but it's not working. I've looked all over the site and can't find instructions on how to post pics, it's been years since I've tried and it's a different set of steps now. Will post pics once I figure this out.

[unruhjonny]

I can open two of your pictures.

Your complication is that you are hosting them elsewhere, you need not “upload” if they have already been uploaded to another site.

The way to attach images hasn’t changed in many years - but I would suspect that different forums have different procedures is what happens to be stumping you.

Here is the post notification I received for post #12 with dead links:

Originally Posted by Baba O'Riley

GTO4Ben -- that's very close to what mine looks like.

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And here it is removed with and without the coil cover --

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Here's the bottom of the coil housing, and the part of the manifold it seats on.

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These two links from post #13 that worked:

[Baba O'Riley]

Thanks for doing that... yes, that's the way mine is set up.

jhein -- thanks to you also, that is a very good video on this. Many of the others on YT have to do with setting up an electric choke, not this kind. I'll start with getting the alignment right on the choke rod. Looking around, I see that it's just about the most common carb problem.

[Baba O'Riley]

Update -- this morning, car was nursed to a shop whose work on these old cars I respect. The first thing the guy there asked me was, "when they re-did your motor in the fall, what kind of cam did they put in?" He said it sounded bumpier / more lobe-y than stock. So maybe the specs and settings the carb rebuilder used -- for a stock 400 -- aren't right for this one.

Thanks again to all of you for your help on this.