Olds Qjet problem

Friends 72 carb for his Olds 455 has no vacuum at the choke where the hot air pipe screws in. The Olds carbs have the circular dial type hot air choke. The vacuum should suck in hot air through the small pipe coming from the intake manifold. I know there is a seal where the choke rod goes into the carb. It appears to be there but I need to take it out to see for sure. Anyone with any thoughts on this?

 

If I recall correctly, there are 2 seals and 1 gasket. There is a choke stat gasket that seals the choke stat to the housing, and 2 small rubber seals for the choke shaft. One of the rubber seals is in the choke housing, and the other one is in the float bowl. These seals and gasket used to come in carb kits. You also have to make sure that proper gaskets were used if the carb has been apart, and that there are no restrictions in either the vacuum side of the circuit or in the fresh air side.

The rubber seals typically would become brittle and leak vacuum. It's easiest to remove the carb and work on it on a bench.

 

If the carb has been on the car for a long time, the vacuum passage through the carb should be checked. It may have to be unclogged due to years of buildup. Sometimes it takes a drill bit to get through the buildup. Good luck

 

Thanks guys, I rebuilt the carb about a year ago and It has been sitting. I will have to get it apart and check all the passages and see if all the seals you mention are there. Right now we are getting the car going and finished up. I have the choke blade wired open for now. I have my GSX choke wired open because it is more trouble than it is worth.

 

The vacuum come from a port on the carb that is inside the bottom right "leg" of the the points of the hot air choke body. There is a plastic piece that goes in the carb body there and in the hot air body. There is the main body round seal, and another round seal inside the choke body around the shaft. There should be a small hole in the bottom right of the hot air choke body where the vacuum is pulled from the carb.

I will try to post some pictures later when I get to my carb shop. Hope this helps.

You can check all of these by taking the choke unit off.

 

Pictures. Hope this helps.
Inside the choke.



Back side of choke



Vacuum port on side of carburetor




Here is the vacuum port on the side of the carburetor itself with the plastic pass through

 

Mark, Thanks for these. They should be a big help when we get it apart.