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Posted on Aug 13, 2010
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Secondary on my rochester quadrajet 4bbl wont open up

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cy schousboe

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  • Buick Master 2,002 Answers
  • Posted on Aug 13, 2010
cy schousboe
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It could be several things. It's quite possible that lack of use has made them hard to open. If that's the case then a little penetrating oil and some gentle persuasion will get them working. The top butterflies work on vacuum so you will have to push on them by hand.
It could be that the vacuum pot on the front passenger side of the carb is not working properly.It should connect by a short vacuum line to the top of the carb on the same side. Unplug the hose from one end, stick a finger over it so you don't lose vacuum. There is a long rod off the back of it that goes to the secondary's that should slide when you unhook and hook it back up.
The linkage on the driver's side should move the lower butterflies. Work the throttle linkage by hand, with the car off, and see if they will open. If they don't then liberally spray the linkage with something like WD-40 and work it back and forth. Spray both sides of the carb at the base and in the middle to lubricate the shafts for the butterflies. Work the linkage and spray and it should free up. Make sure that someone hasn't bent the tab that pushes the secondary's open, out of the way.
If the carb has been worked on lately, especially the choke linkage there are lockouts there. If the choke linkage has been taken off and put back on, these lockouts may not be in the right positions. There is a small tab that drops down when the choke is engaged but it can flop around if not correctly installed. You will need a diagram to get the linkage on properly. Most any rebuild kit for that age carb will have a picture of it.
These are your most likely problems. Hope this helps.

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