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yes I mean the choke pull off. I unhooked it, tested it, sucked on a hose and it didnt do nothing. what does this thing do and how can it keep my linkage from going to normal (low) idle?

and as for the linkage setup .I have it setup just like that now with a double spring. Check this picture out:



so I am really in the dark why I ca fix the high idle problem.
 

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lt1silverhawk said:
That looks like a nice setup.

About the choke pull-off, according to "How to Rebuild and Modify Rochester Quadrajet Carburetors", Ruggles says to "vacuum-test the factory choke pull-off and replace as needed." (page 87). If sucking on it isn't working, it might be time to replace it. (Damaged diaphragm?)
okay, thanks for that. But in my setup, I dont need the choke. My engine will start however cold it is, because I run LPG for main fuell and only have regular fuel for backup.

So I will only repair the pull off if it is causing the high idle. And as far as I know, it has no relationship to that. Or does it?

@Willy, thanks for the nice and clear picture. Looks nice and clean!
 

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The choke pull off needs replacing regardless of the idle situation. It controls the opening rate of the secondary air valve. It applies force when it has vacuum applied (like at idle :mwink: ) to the air valve linkage that holds the air valve and everything else attached to it (this depends on the exact carb in question as to what else, if anything, is included) in the proper position.
 

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Discussion Starter · #145 · (Edited)
I wanted to give some updates on the carburetor since the rebuild.




First off, all of the information on this thread was compiled and properly organized into this wiki: "How to rebuild a Rochester Quadrajet 4MV carburetor". A few members have added additional info to what is found in this thread, so please do check it out.




During the rebuild, I did dab 5-minute epoxy over the plug wells as a precautionary measure. The carb was recently disassembled for a clean up, and the epoxy had corroded and had become flaky. It was cleaned off. The wells don't seem to be leaking.






It was noticed during this past dis-assembly that the main well bleed tubes in the air horn were clogged. They were cleaned out using Hobart 770085 Welding Oxy-Acetylene Tip Cleaner. The procedure involves dissembling the top end of the carb, finding the largest tip cleaner that fits inside the bleed tube, and slowly filing away. Keep moving a size up until its all cleaned out.







Another thing that was missed during the first rebuild was the eccentric plastic cam in the air horn that is responsible for the secondary metering rods. It was found during a recent reassembly in the float bowl body, where the key that operates the choke plate is found. The part was ordered from Cliff Ruggles' site. The kit also included new screws for the air flaps.


The procedure replacing the cam involves removing the air flaps and shaft assembly, and is outlined in the images below.


 

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