304 idle will not kick down

C

coneto

Member
Hello, I have a 304 v8 with a rebuilt junk yard 2210 carb. I am having an issue when I start the car when its cold it runs fine. At about 1500 rpm. But as the car warms up, the idle climbs to 1700 - 1800 rpm. Even though the choke is fully open.
 
I followed those postings. Very helpfull and informative. I thank the person for doing that. No the fast idle cam and all it's leankage moves freely. But I do agree that something might be stuck or is letting in air. I forgot to mention this but I did notice either smoke or steam coming out of a port on the top of the carb. Not coming from the air horn area.
 
Disconnect the throttle pedal linkage at the carb and make sure the idle stop screw is touching the stop after the engine is warm.
I marked up a photo for you. You need to inspect these areas.

22XX IDLE STOP.jpg
 
Sorry for the delay in response. I actually learned something from that pic. I new that the idle stop screw needed to be touching the stop but I didn't know how much. So while the car was running and warm I started to move the idle stop screw and low and behold the idle started to drop. But now the truck has a hard time starting and stay running when warm. I have the two idle mixture screws set to 1.5 turns out. How much do you turn the idle stop screw in and out?
 
I should also say that when the truck is running the whole car is rocking from side to side. Its not rocking hard just a shake and it does this when the car is at 1200 rpm when its warm. Let me ask you this. Could the throttle plate be bad or some other part in the carb be bad and/or dirty?
 
Just a quick update. I re-cleaned the carb and noticed that the power valve piston was stuck open. I didn't have time to check to see if the fix changed anything. So I'll do it tomorrow and post an update of the results.
 
You need to set the two mixture screws for best idle and not a set number of turns out. 1-1/2 is a bit lean but close. Set the speed so it will stay running and slowly turn them in untill the idle begins to slow and then turn them out untill the idle picks up and peaks. Do them both a couple of times. Try to slow the idle speed down as much as you can them adjust the idle mixtures again. Repeat till you acheive the desired idle speed.

One note on an idle that has a rhythmic shake. That usually indicates a miss. Before you dig into a carb issue, get the miss fixed. Do a compression test first.
 
Sorry for the delay in response. I have been dealing with a fuel leak where the fuel goes into the carb. I fixed the issue that I was originally having where the idle speed would not kick down when warm. Now I'm having an issue where the truck will no longer stay running at idle when warm. If I give it gas it does run but when I let off the gas slowly it just dies every time.
 
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