6-pack help!

[65-440]

Ok, so i normally dont ask for much but i'm having trouble with this superbird. 440-6, running very rich, wont hold an idle ... when it does idle it stalls when put in gear. Just went through all 3 carbs, car has been sitting for 2.5yrs, they were nice and gummed up! anyway, timing is at 15 initial, 15" vacuum, outboard mixture screws 1/4 turn out.... outboard carb linkages disconnected, center carb fuel mixture screws all the way in and it still runs. Can see fuel being pulled in from the boosters, only way to stop it is with the throttle blades all the way closed. I have zero 6 pack experience but looking at it like "a carb is a carb" and it is frustrating the hell out of me. On any 4bbl with a function idle circuit, with the mixture screws all the way in it will stall, does a 6 pack not work the same way? I would think it should...What could be causing so much vacuum to be pulled through the venturi with the throttle blade almost completely closed?

 

[Superbeemike]

I’d double check the fuel bowl levels and maybe set the floats a little lower. Also, the needles and seats could be leaking causing the bowl level to be high.

 

[Daves69]

"went through" meaning you rebuilt them?
If yes, what carb kits did you use?
Is the excess fuel flowing only from the center?
Did you reset the float levels and check for flooding via the sight plug?

...... outboard carb linkages disconnected......

Careful here. If the outboards happen to open while running, you won't have the means to mechanically close them with the center throttle.

BTW, There are different gaskets for different style metering plates in the outboards. Recently a member discovered he had the wrong ones installed which evidently caused his flooding issue.

 

[6PKRTSE]

Start with center carb with out board linkage disconnected. Make sure center carb is not off of the idle slot enough to allow the cruise circuit open. Yes, check floats, needle and seats, make sure linkage is not binding, Also, don't over torque the base plate bolts they can cause the butterflies to hang open slightly. Hmm, what else? Mine runs great and always does and starts right up. I don't think I have barely ever pulled the air cleaner since I put the new engine in back around 2006. Has over 55,000 miles on it now.

 

[65-440]

"went through" meaning you rebuilt them?
If yes, what carb kits did you use?
Is the excess fuel flowing only from the center?
Did you reset the float levels and check for flooding via the sight plug?


Careful here. If the outboards happen to open while running, you won't have the means to mechanically close them with the center throttle.

BTW, There are different gaskets for different style metering plates in the outboards. Recently a member discovered he had the wrong ones installed which evidently caused his flooding issue.

Yes rebuilt, with holley kits ... float levels were good in all 3 but I'll double check again this morning. Yes only pulling fuel through the venturi on the center carb.

 

[65-440]

Start with center carb with out board linkage disconnected. Make sure center carb is not off of the idle slot enough to allow the cruise circuit open. Yes, check floats, needle and seats, make sure linkage is not binding, Also, don't over torque the base plate bolts they can cause the butterflies to hang open slightly. Hmm, what else? Mine runs great and always does and starts right up. I don't think I have barely ever pulled the air cleaner since I put the new engine in back around 2006. Has over 55,000 miles on it now.

That's pretty much what I was doing, focusing on the center carb...when I shut down shop last night I couldn't even get it to idle, once I took my foot off the throttle it died.

 

[BB BELLA]

I've never run a six pack but being a little mechanically inclined this is how I would approach a running issue! first thing I'd do is a power balance test! get it running as low of rpm as it will stay running fairly smooth and pull plug wires one at a time see if rpm drops evenly with each wire pulled. doing that at least lets you know your working with 8cylinders and carbs are the culprit and not fouled plug-s or other ignition issue!
my understanding of the 6pac setup is they idle off the center carb! i would remove the two outboard carbs and block off the intake and get the motor idling at proper rpm on the center carb,then I would bolt on each outboard carb one at a time running it each time to make adjustments for the added air flow and confirm that the other carbs aren't dumping fuel when there not suppose to!my.02

 

[Daves69]

Yes rebuilt, with holley kits ... float levels were good in all 3 but I'll double check again this morning. Yes only pulling fuel through the venturi on the center carb.

Myself, I'd pull the center back off and work on it off the engine. Last thing I need is a crankcase full of fuel.
Go back through that carb. Make sure gaskets are correct, not damaged, and are oriented properly. Also verify the needle/seat is shutting down the flow. It takes next to nothing to foul them. Test your float for buoyancy and possible leakage.

https://documents.holley.com/199r8338rev1.pdf

 

[Superbeemike]

65-440....

If the float levels are correct, check the power valve too. If that has failed, it could potentially allow extra fuel to enter the system.

 

[dadeo]

Tough to troubleshoot via forum as can be so many issues, one or combination of issues. Symptoms sounds like lean to me, not rich, fuel dribbling could be 'cause blades are open in transition area so that's why idle mixture screws in all the way are not stalling the motor.
Wrong gaskets-orientation/ruptured power valve/vacuum leak - who knows.
Get it running and as close to idle as you can get. I'm pointing at the idle air bleeds (outers only). One at a time put your finger over the idle bleed , both sides, all 3 carbs and tell us what it does to the idle for each one - stays the same, idle increase, idle decreases. Gains RPM - too lean, loses RPM - too rich.
Maybe we can narrow it down when we get this feedback.
Andy

 

[ACME A12]

my understanding of the 6pac setup is they idle off the center carb!

No. They run & idle on all three carbs. The outboards are always contributing fuel.

 

[65-440]

Myself, I'd pull the center back off and work on it off the engine. Last thing I need is a crankcase full of fuel.
Go back through that carb. Make sure gaskets are correct, not damaged, and are oriented properly. Also verify the needle/seat is shutting down the flow. It takes next to nothing to foul them. Test your float for buoyancy and possible leakage.

https://documents.holley.com/199r8338rev1.pdf

Just put it back together for the 2nd time today and it runs exactly the same, wont even hold an idle now. As soon as the throttle is released it dies ... Float levels good, tested the floats when i had the carbs apart the 1st time weeks ago and they were fine.

 

[65-440]

65-440....

If the float levels are correct, check the power valve too. If that has failed, it could potentially allow extra fuel to enter the system.

Thats exactly what i thought it was yesterday, i swapped it out but it made zero change

 

[65-440]

Tough to troubleshoot via forum as can be so many issues, one or combination of issues. Symptoms sounds like lean to me, not rich, fuel dribbling could be 'cause blades are open in transition area so that's why idle mixture screws in all the way are not stalling the motor.
Wrong gaskets-orientation/ruptured power valve/vacuum leak - who knows.
Get it running and as close to idle as you can get. I'm pointing at the idle air bleeds (outers only). One at a time put your finger over the idle bleed , both sides, all 3 carbs and tell us what it does to the idle for each one - stays the same, idle increase, idle decreases. Gains RPM - too lean, loses RPM - too rich.
Maybe we can narrow it down when we get this feedback.
Andy
View attachment 1241634 View attachment 1241636

Thanks, I'll do this once i can get it to idle! Right now it dies as soon as i let go of the throttle. Right now I'm over this car!!

 

[65-440]

Sent the carbs to Harold Demes....nothing I did worked unfortunately

 

[Daves69]

Sent the carbs to Harold Demes.........

He'll find the issue(s). Let us know!

 

[Moparnocar]

What's your fuel pressure?

 

[Demonic]

Blown Power Valve?

 

[65-440]

What's your fuel pressure?

whatever the mechanical pump is putting out. have had the sight plugs out on all 3 carbs while its running and level stayed good.

 

[65-440]

Blown Power Valve?

Nope, that was my first thought too ... checked it with a vacuum pump and swapped it out for the hell of it.... I did find blockage in the idle metering circuit inside the metering block, got that cleared out and now have a functioning idle circuit but still ran like ****.