Carter AFB question

[rainsucks]

I just picked a '77 GMC k25. It has a carter afb.

On my carb ( this is a pic off the internet but its identical to mine ) , port A is open and port B is plugged off.

Is that correct? or do they both need to be plugged, or both open? What were they originally used for?

Thanks

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[Tyger13us]

I just picked a '77 GMC k25. It has a carter afb.

On my carb ( this is a pic off the internet but its identical to mine ) , port A is open and port B is plugged off.

Is that correct? or do they both need to be plugged, or both open? What were they originally used for?

Thanks

You must be registered for see images

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plug both, there just smog vents and will let dirt and crap get into carb..

 

[MrMarty51]

Maby take a look aroun in here.
Welcome into the forum.

http://www.gmsquarebody.com/forum/forumdisplay.php?f=52

 

[rainsucks]

Thanks Tyger

 

[Jims86]

A is for something that needs filtered air, most of the time, this is a vacuum port on the choke, that sometimes goes through a metal line in the intake or exhaust manifold. B is the bowl vent, and should be plumbed to a charcoal cannister, or back into the air cleaner.

 

[rainsucks]

Jims86.

Since I have an electric choke, I should just cap off A then?

I dont have the charcoal canister and I have a aftermarket chrome air cleaner( with no provision to attach B to ). So on B, should i cap it off or rig up some sort of filter for it?

Thanks

 

[Jims86]

Jims86.

Since I have an electric choke, I should just cap off A then?

I dont have the charcoal canister and I have a aftermarket chrome air cleaner( with no provision to attach B to ). So on B, should i cap it off or rig up some sort of filter for it?

Thanks

Sure, but make sure that choke does not have a vac port. even some electric chokes use them.
As far as B, i woul go get a fitting from the hardware store, and plumb it ito the bottom plate of the air cleaner.

 

[Tyger13us]

Sure, but make sure that choke does not have a vac port. even some electric chokes use them.
As far as B, i woul go get a fitting from the hardware store, and plumb it ito the bottom plate of the air cleaner.

extra work for nothing,, like ya said b goes to the charcoal filter so does a on a dodge..

but!! on carters and edelbrocks? look at the pic,, see that lil square part next to where the power piston goes and the metering rod? on both sides?

those are the bowl vents,, running an extra hose to the air cleaner is a waist of time,, just plug it........

 

[Jims86]

extra work for nothing,, like ya said b goes to the charcoal filter so does a on a dodge..

but!! on carters and edelbrocks? look at the pic,, see that lil square part next to where the power piston goes and the metering rod? on both sides?

those are the bowl vents,, running an extra hose to the air cleaner is a waist of time,, just plug it........

Dont get your paties in a bunch there, buddy. Obviousely, we have 2 differing opinions. He can do what he wants, he is just looking for suggestions.
But, yes, if those are bowl vents under the covers, uncover them, and block B.
Dunno about your emissions inspections there, but they MAY want to see that hooked up.

 

[Tyger13us]

Dont get your paties in a bunch there, buddy. Obviousely, we have 2 differing opinions. He can do what he wants, he is just looking for suggestions.
But, yes, if those are bowl vents under the covers, uncover them, and block B.
Dunno about your emissions inspections there, but they MAY want to see that hooked up.

no problem at all,, it is just nu-necessary for him to run an extra hose to the base of the air cleaner..

the holes in the top of the top plate "the square ones next to the power piston plates on the outer edge's are the bowl vents is what i was saying,, the lil plates with the screws on top of them are where the power pistons go that control the metering rods...

i used to live in the bay area,, sunnyvale to be exact, most of my life really,, had a smog license also way back when,, i live in utah now,, no smog where i live,, he lives in washington and as far as i know and remember from when i lived there? there is no smog check there ether for that year of truck..

but thats beside the point,, all he wanted to know was to plug them or not?

plug um.. or ya can get lil soft plugs for both of those tube ports,, some of those carbs came with them already installed...

 

[Jims86]

no problem at all,, it is just nu-necessary for him to run an extra hose to the base of the air cleaner..

the holes in the top of the top plate "the square ones next to the power piston plates on the outer edge's are the bowl vents is what i was saying,, the lil plates with the screws on top of them are where the power pistons go that control the metering rods...

i used to live in the bay area,, sunnyvale to be exact, most of my life really,, had a smog license also way back when,, i live in utah now,, no smog where i live,, he lives in washington and as far as i know and remember from when i lived there? there is no smog check there ether for that year of truck..

but thats beside the point,, all he wanted to know was to plug them or not?

plug um.. or ya can get lil soft plugs for both of those tube ports,, some of those carbs came with them already installed...

Yeah, i just was'nt sure about Wa....we recently had a member who failed inspection in AZ because some lines were not hooked up to the evap cannister.

 

[rainsucks]

You only have to do emissions here in WA on vehicles that are less than 25 years old and if you live in rural area, you dont have to do emissions at all. I have a kit of vaccuum caps, both ports are getting capped. Ill look at the electric choke and make sure there are no vac ports.

Thanks for all the help.