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1973 with original L48 and Quadrajet and 4-speed. Nothing modified in the 9 years and 11k miles that I've owned it, and no carb/intake/fuel issues prior to this.
Issue 1: after warming up to operating temp, it takes a blip of the throttle to come out of fast idle and back to normal idle. I do the standard start-up procedure... one accelerator stab to the floor, and it starts up normally and proceeds to fast idle. Looking for advice on how to un-stick the mechanism that retracts the choke, or if there is some other fix for this.
Issue 2: Just recently, after a normal warmup, I can take it out on the road and it starts bogging then dying as I let off the gas and coast to a stoplight. Changing the plugs, fuel filter, air filter, and running carb cleaner have not helped. It still starts up and idles normally as mentioned above. After a full warmup, I can pull the air filter and housing off the carb, and the secondary throttle plates on top appear to stay mechanically locked out (see the first part of the video attached). Even running up the throttle past 3500rpm doesn't activate the secondary plates.
Hi Born,
who you want to email is Lars. V8FastCars@msn.com.He is the zen master of Quadrajets. He has a list of what he does to your carb. Gives you details of what has done. I had him rebuild my carb on my 1972 3 years ago. Still runs like new. I & a lot of the forum members recommend him highly.
I see nothing wrong with your 1st issue. You have to blip the throttle to release the tension on the fast idle cam.
Your video indicates you dont understand that the choke pull off has vacuum applied to it preventing the secondary air valve from being pushed open by your finger.
You also will not get the secondary air valve to open by revving the engine in neutral.
Have you checked dwell and timing before assuming the carburetor is causing your bog?
Assuming dwell and timing are correctly set, have you adjusted the idle speed and mixture screws?
I see nothing wrong with your 1st issue. You have to blip the throttle to release the tension on the fast idle cam.
Your video indicates you dont understand that the choke pull off has vacuum applied to it preventing the secondary air valve from being pushed open by your finger. You also will not get the secondary air valve to open by revving the engine in neutral.
Have you checked dwell and timing before assuming the carburetor is causing your bog?
Assuming dwell and timing are correctly set, have you adjusted the idle speed and mixture screws?
Correct. The secondaries open under harder throttle conditions, but needs the vacuum to activate if I recall correctly. Not just speed of engine, but the load.
All other points, great advice!
Last edited by 73sbvert; Jan 21, 2021 at 06:43 PM.
Two Quadrajet issues
