With the dropping temps I have been having more and more difficulty with my cold starts. It appears that my choke butterfly is working properly and my high idle cam is functioning and steps down when I command it. Once the motor does fire (which takes some convincing) it will idle for a few minutes then die. If I hold the throttle open to a certain rpm and hold it there then it will snap up to that rpm and fade off to a stall. This is a new one for me. I'm basically at the point where I have to sit in the car for 10-15 minutes feathering the gas just so it will idle. Once warmed up, it starts first crank, no gas every time (albeit a lumpy idle but that may be timing related. One thing at a time here) The tag on the carb is an 8145S and I rescently installed a 195* thermostat. My timing is about 10* initial. All help is appreciated, I miss my BBS.

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Vacuum leak? Metering rod adjustment?

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Casually looking for a Clifford hyperpak intake for cheap.

Where'd this carb come from? What (exact) choke setup are you using? Sounds like the choke might not have enough spring tension pushing/keeping it closed. Another thing to check is whether the choke plate is hanging on the air cleaner bail — try removing the air cleaner bail from the carburetor before your next cold start and see if anything improves. You mention extended crank time; this suggests either the choke isn't closing all the way or the carburetor is empty in the morning. Have you done the fuel line mod or still running stock fuel line routing?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

My BBD takes some to start it cold too. I have to give it lots of gas when its starts, otherwise it will idle for 10 sec then die. Afterwards it will idle rough for about 2 min and then be fine.

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'74 Duster 225 Super Six w/904
14" Cragar SS wheels

I'm using the spring/rod that came with my super six, sorry, the carb is a mystery at this point. With the air cleaner off (cold) I can hit the throttle and the choke will snap shut. When I crank, the choke will open a bit before it dies and goes back to closed. This may be a worn spring symptom for sure. The mystery is really once the choke is all the way open and the throttle will drop off from wherever I hold it (900, 1100, 1250). My fuel line is high and dry, routed over the VC, though it is steel.
My digital camera is on vacation so no close up shots but here is an older engine bay pic.

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You may want to try adding some closing-tension to the choke manually with your fingers; remove the air cleaner, operate the throttle so the choke snaps shut, then add extra closing pressure on the choke lever as you crank the engine from under the hood (or a helper does it from the driver's seat).

It's also possible-to-likely that your choke pulloff is pulling the choke too far open; you may want to spread apart the legs of the U-bend in the choke pulloff link so there's less pulldown action. If you go too far in this direction, the engine will load up and blow soot after a cold start.

(My quick 'n' dirty prescription would be a better carb and an adjustable electric choke kit...and no, I'm not just saying that because I have a couple brand-new Super Six carbs left )

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I would check the diverter valve in the exhaust manifold. Does it work? Is there any frost on the base of your carb?

In this neck of the woods. When the temps start to go below 50 degrees and the mornings are dewy, you get a condition know as "carb icing". This is when the air starts to literally freeze as it passes thru the carb. When this happens, frost starts to appear on the base of the carb. This frost will then actually start to restrict the fuel delivery.

So you start your car, it idles for a couple of minutes and then dies. You do it again, and again, and again. After about 5 trys it starts to run OK. What has happened? The exhaust manifold has finally transfered enough heat to the intake manifold so the base of the carb is above 32 degrees.

Adjusting the choke will not solve this problem. Doing the "fuel line mod" will not fix this problem. Changing over to an electric choke will not solve this problem. Heat at the base of the carb will solve this problem.

Carb icing could account for poor running after the engine starts and runs a few minutes, but not for the extended crank time and immediate die-out.

Pat, what kind of air cleaner are you running? Thermostatic or plain?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Plain modified top SS base (you know the one) with an open element. I have done all my checks with and without the AC on. I'm really doubting the carb base icing theory. I think it could be a real problem for some but it just hasn't been that cold here yet and it's been happening with 0+ evening temps. Plus the symtems are hard start, run for a few minutes, die, then really hard to keep going. The diverter valve works perfectly. Keep the awesome suggestions coming, tomorrow morning will be some good scientific problem solving.

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More specificity, please: Start up, run okay for a few minutes, then stall? Or run for a few seconds, then stall?

(Air cleaner: Oh yeah, duh...)

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

That would be a couple minutes then die. It almost seems like once it catches to start with that everything will be alright. Then it all goes bad. hard to re-start and like I mentioned earlier, throttle speed falling off as I hold the throttle steady. Weird.

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Well if it is a couple of minutes then it definitely could be throttle plate icing, and you might well never see it on the outside of the carb. The ambient conditions you describe are perfect for it, just like Kesteb says. This is why these carbs were originally equipped with thermostatic air cleaners. You might make creative use of a hair dryer to see if warm air to the carb makes the problem go away.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Alright, here's where I'm at. I hit throttle (all from under hood) and the choke snaps shut. Crank the engine until it fires, the choke blade opens 1/8" where I can see fuel shooting in small bursts from the increased vacuum. Manually start closing the choke plate causes a stall; manually opening a bit creates higher rpm and happier mixture. I squeeze the "legs" of the choke pull-off link and it idles perfect but the choke is pretty much wide open in a couple minutes (still on the high idle). Today was a sunny Fall day so the icing condition wouldn't have played a factor. Tomorrow morning will really be the acid test.

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Ah...you didn't mention black smoke, so I didn't think to mention a too-rich mixture! Give it a try tomorrow AM and see what happens.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Pat,

Dan is right on with his explanation.
My carb did exactly what you described about a week ago, when it started freezing here. Mine was too lean because the pull-off was opening the choke too far.
However, in your case it sounds like your just the opposite, same symptoms, but from over choking......it doesn't take much adjustment.

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Aggressive Ted

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74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG