Idle RPM carb problem

[LukeSkywalker]

Car almost done now. Went through EU control no problem. Starting to look real pretty with all that new chrome everywhere and all that.

One problem left though. It's a 440 with a six pack carb setup.
I've had to disconnect the centre carb vacuum hose from the front and rear carb to get it to idle properly..

The car starts fine and idles properly (1000rpm) when cold. I drive it abit, it gets warm and then it idles at 2000-3000rpm. Even if I stop and start engine.

What happens is the vacuum from the centre carb hose pulls the front and rear carb-valves on abit. And when I stop the engine, it seems the vacuum still keeps the valves on, because they don't want to return even with engine off... Not for a while anyway. If I let it rest for a while it returns..
As it stands with the front and rear vacuum hoses disconnected, it runs fine all the time, but I'd like to have it setup up like it's supposed to be, and use the front and rear carb when I want to..
I've looked at the rods that connect the centre carb to the front and rear carb, and its those rods that push the centre carbs idle position upwards.

Is it simply a rod adjustment problem, cause I figure I can adjust the rods so that the centre carb has abit to go on before idle gets pushed upwards by the rods connected from front and rear. As it stands the rods are aligned like the service manual says. The centre rod is on the bottom when perfectly fitted with the front and rear holes. So its got nothing to go on when front and rear carb starts pushing..

Or is it faulty vacuum? Are the front and rear vacuum valves not supposed to move at all when at idle?

[Chryco Psycho]

There should be no vacuum to the secondaries , there are 2 vacuum ports side by side on the center carb , the the one out of the metering bock goes to the dist the second one pointing forward si for the secondaries , there should be no vacuum from either port though .
 The linkage to the secondaries should force the secondaries all the way closed but should not hold the throttle open on the center carb , do you have enough spring pressure to pull it closed properly ?

[LukeSkywalker]

Sorry for late answer. Played football. Hospital. Surgery. Left achilles tendon snapped clean off.. Now I dont have a choice. Cant clutch. The Cuda is the only auto trans I own...
So sort of a win win situation..

The spring is very tight as is. I tried thightening it further, but no difference. When the vacuum pulls the two carbs on, its so strong, I cant even push back down the lever(that is supposed to hit a solenoid) with my hand..
I have simply plugged the distributor/vacuum, cause there is no vacuumcontrol on the new dist I got with the MSD ignition kit. Maybe I shouldt have plugged that.. Could plugging that somehow increase the vacuum on the secondaries?
Could the secondaries vacuum membrane be faulty somehow? I should think not as they basically do what they are supposed to, just abit much.

I think I'll try the rod adjustment, and sort of let the secondaries have some play before it starts pushing the centre idle up..




EDIT: - When there is no dist-vacuum, are you supposed to plug the metering dist-vacuum outlet, or leave it open?[B/]

[Chryco Psycho]

I have plugged it to prevent air getting in that way , when it is attached to the dist it is plugged as well .
Ouch on the tendon that will take a while to heal up !!

[LukeSkywalker]

Thanks Chryco, you've been great help !    Looked for a donations link for this site but cant find any.


 You wouldn't happen to also know where the front carb hose that's marked with an arrow is supposed to go, would you? (OLD PICTURE !)
When I got the car, that was hooked to the dist vac... for some reason..

Cant find it on any other six pack pictures I've googled...

[tman]

Here are some very detailed photos of 69.5 6pk.  You can click on the photos and zoom in.  My center carb has the 2 vacuum hoses where one goes to dist and the other that connect with the other carbs.  Your front carb has both, so your setup is different. 

http://www.moparaction.com/Article/SIX-PACK_SERENADE/6.jpg

[LukeSkywalker]

According to that pic and all pics I have seen, that outlet pipe on the top front carb isn't supposed to exist. Maybe I should just leave it open..

Also the nozzle plug for the dist.vac on the metering is gone. Anyone know where I can buy a new one?

[Chryco Psycho]

the one the arrow is pointed at is for the dist advance , the other one beside it is for the outboard carbs

[ek3]

there should be no vacuum @ idle speed  to the outboard carbs. check that first. your idle speed should be around 1000 rpm [ w6 pk cam 4spd ]   if you have vacuum @ 1000 rpms then you are connected to a constant manifold port.  it appears that your center carb has only one port where there is usually [2 ],the one thats visable looks un-drilled .  one upper for dist, one lower  [with 2 way  a splitter] for outboard carbs. what carb number is that center carb? if it is not vacuum holding it open then it almost has to be mis -adjusted rods. you have to hold them tight when adjusting.   the big question is how do you have  vacuum holding them open when its hot and not when cold ?  hamtrack reg. has a page on rod and solinoid adjustments for six packs .. odd looking carbs if u ask me . my 2 cents worth.

[Chryco Psycho]

the picture above is not you car correct ??
 you could have the wrong metering block or gaskets in there