6 barrel idle settings

[Sonny]

Just got my six barrel setup running and it’s time to tune it. I’m using Holley tri power mechanical carbs.

question is do you set up all three carb’s idle mixture screws equally or does the center carb do all the idle work? If I do the later, it idles good but in gear under Load it stalls like a vacuum leak (outboard carbs). As I give the outboards idle fuel, it gets better. Wondering what was the right way to do it.

 

[kiwigtx]

I suggest you have a good read of this thread....excellent information and well laid out...

https://www.forbbodiesonly.com/moparforum/threads/tuning-a-six-pack.131693/

 

[BSB67]

This is the non Mopar mechanical outboard carbs, correct?

And what exactly what "idle" screws are you talking about.

 

[BSB67]

I suggest you have a good read of this thread....excellent information and well laid out...

https://www.forbbodiesonly.com/moparforum/threads/tuning-a-six-pack.131693/

Funny. I hate it.

 

[Sonny]

This is the non Mopar mechanical outboard carbs, correct?

And what exactly what "idle" screws are you talking about.

Sorry I meant “idle mixture” screws.

 

[Sonny]

This is the non Mopar mechanical outboard carbs, correct?

And what exactly what "idle" screws are you talking about.

And yes to the setup. Not Mopar. I know I have to go elsewhere for secondary tuning advice with progressive mechanical linkage.

 

[kiwigtx]

Funny. I hate it.

And the beauty of this site, is that we can all have our own opinions about anything.

 

[Sonny]

I suggest you have a good read of this thread....excellent information and well laid out...

https://www.forbbodiesonly.com/moparforum/threads/tuning-a-six-pack.131693/

Perfect. Sounds like I was on the right track with all three carbs contributing to idle fuel Supply. Great read!

 

[RJRENTON]

Just got my six barrel setup running and it’s time to tune it. I’m using Holley tri power mechanical carbs.

question is do you set up all three carb’s idle screws equally or does the center carb do all the idle work? If I do the later, it idles good but in gear under Load it stalls like a vacuum leak (outboard carbs). As I give the outboards idle fuel, it gets better. Wondering what was the right way to do it.

View attachment 938093

IMO...
With the origional Holley set up, the end carbs have an idle circuit and adjustable mixture screws, albeit very difficult to access on the rear carb. Looking at your pix, the Holley's you have selected have a easily adjustable idle mixtures. It would be my opinion to use a combination of all three carb's idle mixtures to achieve a desirable idle, favoring the primary carb (center) while allowing each of the end carbs to contribute ~ 1/4 (each) of the total required. Because your system's carbs have accelerator pumps, especially the end units, will allow or should tolerate a slightly leaner mixture, when opening. BTW....are all 3 carbs of equal CFM or they similar to the Mopar vacuum carb specs? You MAY need to experiment with the end carb's jetting or float levels to achieve a smooth transition upon the end units opening. Do both end carbs open together or does one proceed ahead of the other?....as this may affect the overall objective. The cam selected and the ignition advance setting will also effect idle quality. Just talking out loud....
BOB RENTON

 

[Sonny]

IMO...
With the origional Holley set up, the end carbs have an idle circuit and adjustable mixture screws, albeit very difficult to access on the rear carb. Looking at your pix, the Holley's you have selected have a easily adjustable idle mixtures. It would be my opinion to use a combination of all three carb's idle mixtures to achieve a desirable idle, favoring the primary carb (center) while allowing each of the end carbs to contribute ~ 1/4 (each) of the total required. Because your system's carbs have accelerator pumps, especially the end units, will allow or should tolerate a slightly leaner mixture, when opening. BTW....are all 3 carbs of equal CFM or they similar to the Mopar vacuum carb specs? You MAY need to experiment with the end carb's jetting or float levels to achieve a smooth transition upon the end units opening. Do both end carbs open together or does one proceed ahead of the other?....as this may affect the overall objective. The cam selected and the ignition advance setting will also effect idle quality. Just talking out loud....
BOB RENTON

Thanks Bob. The center carb is 325 and the outer carbs are 350. I am waiting on a side hung bowl for the front carb as it needs to be shorter to work with the 6 pack base. Haven’t gotten to the outer carb tuning yet but thought I would have them come in together and see how that goes first.