440-6 idles at 3500 rpm!

[351c4v71]

Hi guys, finally got my first 71 cuda ... well barracuda.
it's got a 440 6 pack in it and it idles at about 3500rpm!
Also a loud "pock" noise comes out of the mufflers every now and then...don't know how to describe it.
So I tried to unscrew this bolt on the middle carb to lower the rpm but it's at its lowest already. If I unscrew it, it just hangs there and doesn't touch any part of the carb. the throttle is stopped instead by a small piece on the other side (passenger side).
I don't know the terms as you can see but want to learn.
Anyone got any ideas?
Thanks
JS

[footin70rt]

First check and make sure the choke linkage moves freely and the choke will open all the way, then see if the throttle sits on the idle speed screw. Also make sure on  the outboard carbs that the the throttle blades are fully closed both with the engine off and running. Good luck!   

[Chryco Psycho]

disconnect the linkage to the outboard carbs , it should idle down , adjust the lenght of the linkage so the carbs are all full closed , if this doesn't work start looking for vacuum leaks

[AMXguy]

If it's stopped by a piece on the passenger side that would be your fast idle which runs off the choke.  sounds like you need to adjust that down a bunch, but check to make sure it's opening with the choke as it should.

[351c4v71]

I'll try that tonight, thanks.

Could it also have anything to do with the distributor advance?

[MEK-Dangerfield]

I'll try that tonight, thanks.

Could it also have anything to do with the distributor advance?

I can't see it affecting the idle this much. You could unplug it from the carb and hold you finger over the carb port to see if it changes anything.

Are you sure your tach is accurate? At 2500 RPM, the sound almost makes my ears bleed.   

[Chryco Psycho]

the gasket under the carbs could be holding the throttle plates open also , to get them off it is easiest to work from the back , take off the rear carb then the middle , then the front

[351c4v71]

Had the 3 carbs completely dismantled and rebuilt by a supposedly pro.
At least there are no more gas leaks.
I thought I had it fixed after playing around with the idle screw and the 2 small fuel mixture screws on each side of the center carb. However, took it for a good drive today, about 30 minutes. After about 25, the idle went high again, like about 3k high. Had to turn the car off at the lights! So when I got home I played around with the center carb again. Only managed to get an ok (around 1200-1500rpm) idle when I screwd completely (clockwise) the 2 fuel mixture screws on center carb and unscrewed completely the idle screw. What the hell!
And I know that tomorrow morning, when the engine is cold, it wont hold its idle and just die on me.
Any ideas?
I've attached pictures that may help.

[Chryco Psycho]

is the front linkage too short or the rear one too long , holding the center carb open ?? You can disconnect the linkage & set it up using the center carb & then adjust the linkage so it is loose when it goes into the end carbs .
 in the rear of the center carb there is a small cover with 2 screws holding it on , inside there is a small double strip of metal with a plug on one end , make sure that is in there & the right way . there are idle mixtures on the outboard carbs also in the base plate under the bowl , the rear one cannot be adjusted in place but I usually set it about 1/2 out , the front can be adjusted .
 Let me know what you find

[jimynick]

It looks like this thing has a step-up solenoid to advance the idle when the a/c is on. Is it touching the idle arm and holding it on a fast idle? It appears to be under the middle carb. 

[Chryco Psycho]

It looks like this thing has a step-up solenoid to advance the idle when the a/c is on. Is it touching the idle arm and holding it on a fast idle? It appears to be under the middle carb. 

definate possibility most systems eithe do not have them or they quit working years ago .... they are adjustable you can either thread them down or tweak the linkage

[351c4v71]

It looks like this thing has a step-up solenoid to advance the idle when the a/c is on. Is it touching the idle arm and holding it on a fast idle? It appears to be under the middle carb. 

Is that what that is???
I know the car originally came with AC but now doesn't (440-6 can't I'm told).
So this solenoid is for AC???
I think you are right that when hot it is holding the throttle high. Is it possible that it moves up when engine is hot. I removed it and it seemed way better. But I didn't get a chance to go very far.
How many turns to you give on both fuel mixture screws on the middle carb???
I'm at 1.5 and it dies out on me when engine is cold (maybe due to choke plate being tied open?) but when hot, keeps a good idle, maybe a tad high. But sometimes I can hear some little backfires when hitting the gas. Do backfire means to rich or not enough gas? Previous owner installed a fuel pressure regulator which might cause me some problems as well I guess.

[Chryco Psycho]

The idle solenoid is supposed to maintain the idle speed then drop down when the key is shut off to stop run on . It can be adjusted for idle speed but really is not needed . The A/C cars have a similar set up for raising idle speed but A/C & A 6 pack was never done by the factory .
 I adjust the idle mix screw on the the engine when the engine is warm & @ idle speed , the setting will vary
 usually a backfire as the carb is opened is a lean condition , is there any play in the accelerator pump linkage ?  There should not be