another c-3 carb question

[Jay Hastings]

does anyone know if their is anything that connects to the long vacuum tube
that comes out in between the choke set up, or does it get caped?
it is a 73 4-speed 454 Q-jet #7043201
thanks jay

[Joe L.]

Re: another c-3 carb question

Jay------

The tube to which, I believe, that you are referring is NOT a "vacuum tube". It is a vent tube. There is nothing attached to it and it, most definitely, should not be capped.

[Patrick H.]

Re: another c-3 carb question

It's interesting that you say this. I've seen vacuum tubes connected here many times (not necessarily correctly), or otherwise seen it capped. It's a rare car that I've seen with it open to atmospheric pressure.

If it is supposed to be "open and free", what does it connect to internally, and what does it do?

Patrick

[Joe L.]

Re: another c-3 carb question

Patrick-----

I believe, perhaps incorrectly, that the tube in question is the tube which is found "between" the choke plates and rises vertically from the carburetor air horn assembly. This tube, which is about 5/16" ID, is a vent and has no attachments or capping, whatsoever.

If the tube referred to is the HORIZONTAL tube which emanates from the right side of the carb float bowl assembly, that tube is the vacuum source for the A.I.R. diverter valve and, sometimes, other engine emission control components.

[Harmon C.]

Re: another c-3 carb question

I have seen this tube with a black rubber cap on a 73 454 Bowtie with 4000 miles. I checked my pictures to make sure. L- 48's are the same. L-82's I only have one Bowtie example and it has a hose on it and may be going to the TCS solenoid. Lyle

[Patrick H.]

Re: another c-3 carb question

Joe,

Yes, I believe that Jay and I are referring to the tube that pokes out horizontally between the choke linkages on the right (passenger's) side of the carb.

Patrick

[Clem Z.]

Re: another c-3 carb question

that is the vacuum source for the heat valve on the closed air filter air intake but if you have a open face air filter it should be capped. IMHO

[Patrick H.]

Re: another c-3 carb question

My closed 1971 and 1972 air cleaners HAVE no air valve. Dontcha love it. No wonder it's capped.

I'll have to check the 1970 Cutlass to see what it has.

Patrick

[Jay Hastings]

Re: another c-3 carb question

Thanks Guys
the tube that i am talking about is the one on the right side and it comes out right behind the vacuum can. for the secondaries.
mine has a black cap on it. over the weekend I looked at another 73 454 4-speed suposidly having 38,000 original miles (more like 138,000 or how long was that speedo broke?) anyway it had a hose connected to this tube and I knew that hose didn't hook up their, but it made me think what is this tube for?

Jay

[Jay Hastings]

Re: another c-3 carb question

I bet you are right clem

Jay