Help - Vacuum Connection on Carter YF

The picture is of the old 170 in a 71 Bronco.

What does the vacuum line that runs from the top of the carb to the intake manifold do? is this connected to the proper vacuum source?

http://imageshack.us/a/img189/47/a9s3.jpg

I think that's the one that delivers warm air to the intake to aid cold start-ups.
Does it go down to a port on the exhaust manifold?

Jackfish, it goes to a vacuum block that is on the intake manifold; I'm not sure it should be hooked up this way, it was the way it was from the day I bought it.

There is a heat line from the exhaust manifold that goes to the choke.

Rick.

That top vacuum port is as JackFish said, to supply clean make-up air to the tube which is part of the exhaust manifold. Once the air is heated, it goes through an insulated metal tube to the choke housing. This hot air is drawn into the choke housing by a small vacuum port located within the choke housing.

The carburetor is jetted to compensate for this controlled vacuum leak. If the vacuum tube now goes directly to the vacuum tree on the intake manifold, you have quite a vacuum leak.

Thanks for the information!

Just so I have it clear the top port pictured is for clean make up air and should not be connected to anything? I can unplugged it and leave it open to the air?

Thanks again!

You can also check this below link shows vacuum line runs for the different years of Mavericks. It should be about the same for yours too. Good Luck

http://1bad6t.com/Maverick/repair/emission.html

rae61":2n9ezt75 said:

Thanks for the information!

Just so I have it clear the top port pictured is for clean make up air and should not be connected to anything? I can unplugged it and leave it open to the air?

Thanks again!

Click to expand...

It should be connected to a metal tube which passes throught the exhaust manifold and on to the choke housing, but can be capped off. Do not leave it open to the air.