Need help identifying line from carburetor

Howdy All, I'm new here. I need help identifying where a line from the carb should be running. It is the line that comes off the back of the carb on the Choke side (rear of the choke tube). It has a short rubber line that goes to a steel line. That steel line runs along beside the choke tube, kicks back near the exhaust manifold, and then is open. It appears that it should have another rubber line from there, but not sure where to. I have added a couple of photos with some crude circles around the mystery line.





Back story on the Bronco - Recently acquired a 1971 Bronco via a family connection. It has not been running in about 10 years. Got stowed away in the garage when the Carb gummed up. A remaned carb was purchased, but never installed until the grandson recently installed it against desires of owner. I picked it up with the carb questionably installed, and with the bracket on the end of the throttle shaft bent from an apparent drop. I have ordered another remaned carb from Rock Auto. Want to figure out any additional issues I am going to run across while I am waiting for the replacement carb, like this mystery line.

The exhaust manifold has an inni and an outie for heated air for the choke. Clean air goes through the top of the carb down the rubber hose into the steel tube. The tube goes down under the exhaust manifold. The tube is pressed into the steel boss below where your upper tube comes out the top. The top tube goes over to the choke on your carb. The choke when cold opens a vacuum leak to pull heated air through those steel tubes until the choke cap gets heated enough to open up the choke when the engine is warm. Once the choke opens it blocks off the vacuum port that pulls the heated air in. Once the engine gets cold the cycle starts all over again.

Thank you! So, I'm guessing that the line came out of its fitting (will have to put eyes on it tomorrow). I know that the choke tube (going directly to the choke) is fairly loose at the manifold. How tight of a fit do I need there? Since vacuum is being used, does it need to be air tight? Not a lot being run off of vacuum, so I wouldn't figure a small vacuum leak would cause me too much issue.

See attached picture.

You should go to the Lone Start Early Bronco Club meet and greet, see some Broncos and meet so super cool and knowledgeable folks.
East Texas Meet & Greet
Location: Cottonwood
3422 N Shepherd, Houston, TX
Date: February 18, 2018 at 2:00 pm

Aggie_00 said:

...I know that the choke tube (going directly to the choke) is fairly loose at the manifold. How tight of a fit do I need there? Since vacuum is being used, does it need to be air tight?

Click to expand...

It's probably the loosest of all the vacuum related fittings, but does not usually cause any issue. So you don't have to clamp it or anything.
If the hose is literally falling off though, replace it with the correct size and head down the road.

If you were to leave the choke cover itself off though, it's just enough of a vacuum leak to let itself be known.
It's a very tiny orifice through one of the legs of the choke housing and actually has an o-ring seal (some standard rubber, some just flat paper) that often comes in the re-build kits.

While the system is not absolutely critical to the running of the engine, it does help warm it up quicker to get keep the overly rich mixture from staying around too long. So it's good to keep it working anyway, if you can.

If your area has detailed safety/smog inspections too, they may call you on it when the parts are obviously disconnected from old age.
But you can make your own if you have to, to pass most inspections. They just want the heated air going into the choke. Doesn't usually matter that it's factory or not.
Unless your inspectors are real sticklers for that kind of thing that is.

Welcome to classicbroncos too by the way. In both aspects!
Welcome to the site, and welcome to the finicky world of old classic Broncos!

Paul

Thanks everyone for the help!
Rustytruck, my set-up looks identical to the picture that you attached. If it rusted off, the part that was in the plug on the bottom must have rusted completely away. No sign of any remnant, and I was able to push the end of the line into the plug (I am sure that it will fall out as soon as I get the engine started, not much room between the frame and starter to get any real leverage). Does that plug on the bottom side of the exhaust manifold come out, or is there a good way to get the old, or a new line to stay in the old plug?

PaveBronco, I am working all weekend, but keep me posted on future meet-ups. Is there a Facebook group or some other way to keep up with times & dates? I also have a '66, F-250, Custom Cab, Camper Special, and am involved with the Slick 60's group, but am usually unable to make meet & greets due to work schedule. I do like the 2:00pm meet up time, though, would allow me to make church, and the meet on a Sunday I had off.

Dirt Donk, fortunately, I live in Texas! Diesels, and anything 25 years or older, only has to pass a basic safety inspection. Currently I only have 2 vehicles that have to pass emissions, and this will be the last year for one of them ('94 Jeep Wrangler). My sister & brother-in-law had a stint in California, so I have an idea of what you are likely up against keeping old iron on the road. Thanks for the warm welcome!

Put a punch inside the tube and wiggle it around a bit to slightly flair the tube end making a little tighter fit.