Vacuum choke

[GMAN69]

I have a 69 D100 225. I had a carter one barrel with issues. My son got me a Holly One barrel with vacuum choke. Runs great but I'm not sure what sets the choke, does it still have to be set manually.

[dodgeboykim]

Vacuum is a pull off to open when warmed up. Sounds like you may have an automatic choke carb instead of a manual cable operated one.
Pictures will help.

[Chaulky]

I think i have the same this going on, brackets are weird and it seems like an auto choke not the manual maybe?

[PwrWgnDrvr]

Everything with that carb/choke is homebrew modified.

[Chaulky]

It definitely is, should I just do away with the cable and let the auto choke do its thing if that is what is on the carb? Can anyone tell if that is an auto choke?

Thanks

[PwrWgnDrvr]

Looks kinda like it, but I can't say absolutely.
Does the cable setup work? If so, why change it? I prefer a mechanical choke a thousand times more than a vacuum choke.

[Chaulky]

Not very good, it's either hard to pull or gets pulled out of the bracket. I havnt had much luck finding the right one so maybe I'll redo the cable with something else that I can make a better bracket for.

[martincom]

I've always had good results with a properly setup automatic choke. I see the well for it in the intake manifold.

Also, that carb is from quite a bit newer engine, as evident by the float bowl vent valve. So it will likely require some changes to rich'en it up, if that engine is in '69 configuration.

Also, you'll want to remove that cap from the float bowl vent valve. Normally, that would connect to either the cankcase breather or a charcoal canister, to prevent the fumes from being vented to the atmosphere when the throttle is at idle position.

With it capped, when a hot engine is shut off, the gasoline in the float bowls heats up quickly and vaporizes. Normally, those vapors would escape through the bowl vent valve that you have capped. With it capped, they are going to escape through the internal bowl vent -- that tube in the center of the throat with the top cut off at an angle. When the vaporized gasoline vents out that tube, it contacts cool air, condenses, and falls into the throat, flooding the engine.

[PwrWgnDrvr]

Martin is correct that it is not an auto choke. Auto chokes are controlled by manifold heat that opens the choke slowly as the engine heats up. The vacuum dash pot on yours functions to open the choke a little, after the cold engine starts, when there is an auto choke. Otherwise, a fully closed auto choke would immediately flood and kill the engine.

[swptln]

As Terry mentioned, the vacuum pull off is designed to open the choke when the engine starts. There is a setting for it, but it only will work with the automatic setup. The cable setup you have or any other one will not allow a pull-off to function. If you install the original thermo setup on the manifold stove and go through all the choke settings, fast idle, etc. it should work fine. If you stick with the cable...you can pretty much eliminate that pull off vacuum diaphragm.
More often than not, those later model carbs with all the pollution crap on them might run a little on the lean side, as they were mostly setup for fuel mileage.