New to slants, and cars in general. I have a new Holley 1920 installed on my 69 valiant. 225 engine. I replaced the carb because the last one was in desperate need of a rebuild and was pretty intimidated about rebuilding it myself and potentially being without transportation if I screwed up.

The new carb runs great after tuning, but seemed to run real bad when cold. And I think I narrowed down why. With the new carb, when I pump,the gas the choke doesn't close. Nothing appears to be missing, and I can manually close the choke just fine. The arm connecting to the intake is the same and hasn't been changed. What could the problem be?

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69 Plymouth Valiant

The choke thermostat which bolts to the exhaust manifold needs to be adjusted to close the choke flap. Adjust it in the morning before running car. It should firmly close the choke flap completely shut, but not too tight. This is if your thermstat isn't broken.

Welcome on the board. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download. Choke adjustment information is here.

You probably need a new choke thermostat.

Also: Tune-up parts and technique suggestions in this thread. And get the three books described in this thread.

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

Perfect, worked like a charm. I knew it probably had something to do with that arm (choke thermostat) just didn't know that there was a way of adjusting it. It was a little tight, so lubricated it a bit and gave it slightly less of a bend and it worked perfectly.

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69 Plymouth Valiant

Oof. Lubrication is not appropriate on that mechanism, and the adjustment is made by removing the choke thermostat from the manifold, loosening the clamp nut, and rotating the spring plate. Not by hamfisting the rod.

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

Did that first, but it was already in a good position. I think the rod was just bent too much by the previous owner. Although the choke worked fine with the previous (bad) carb.

Hope lubricating the mechanism and arm wasn't too bad of a mistake though. It's working, at least.

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69 Plymouth Valiant