Follow-Up Question to AFB Vacuum Question

[Richard Wathen (34281)]

In his September 30th question about his 1965 Carter AFB, Brian Monticello asked about the vacuum inlet on his AFB. My follow-up question is what, if anything, does the other end of the vacuum tube that slips behind the exhaust manifold hook into?

Thanks,

Dick

[Duke Williams (22045)]

Re: Follow-Up Question to AFB Vacuum Question

It's sounds like you're talking about the choke clean air system.

There is a small vacuum port on the main body that communicates to the choke vacuum break piston in the choke housing. The port is sealed with a small O-ring between the main body and choke housing.

Clean air routes from a nipple on the air horn via a rubber hose to the vertical tube between the exhaust manifold and head. The tube loops back under the manifold and into the manifold, which has a pressed in tube. This heats the air.

From the internal manifold tube the heated air travels through the chrome plated tube from the top of the manifold to the choke housing where it heats the thermostatic coil, pulls the choke vacuum break and on to the carburetor body through the O-ring sealed passage and into the inlet manifold.

Duke

[Richard Wathen (34281)]

Where does the tube loop back under...

...the manifold and into the manifold? Does it go into a hole in the front section of the "rams horn"?

Thanks again.

Dick

[John Hinckley (29964)]

Re: Where does the tube loop back under...

Dick -

The tube loops down below the manifold and comes back up, inserted into the hole in the bottom of the manifold just forward of the manifold outlet; shown in the 1965 A.I.M. in UPC6, Sheet C2, also UPC L75, Sheet 1, and there are photos on page 224-225 in Noland's book.

[Richard Wathen (34281)]

Many thanks! *NM*