Asked by May 23, 2016 at 10:43 AM

Question type: Maintenance & Repair

I have a 1978 quadrajet. It has no idle mixture
screws..why is that..My 64 impala smokes out
driver's side primary when I shut it off. My
headers are slightly red. I advanced the timing
and that helped a lot. I am still curious why I
don't have mixture screws...only a choke to rich
en or lean......Can anyone help???

2 Answers


They are there you have to punch out the metal plugs where the air bleeds screws are located, and to do it right the carb will have to be removed, the base carefully slotted just enough to get a punch behind the plug and drive it out.


Sounds like you may need to overhaul the carb anyway, from the way you stated things it sounds like one side is lean and the other rich, and it most likely hasn't been updated for this garbage they call fuel today. I have also found that some of the older vehicles need the distributor recurved and the vacuum advance reset so it can run this stuff a little better. And don't forget the lead substitute in the fuel tank if you haven't had the engine's valves and seats redone.

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