Fuel System: AFB Carbs

[Lou Van Anne]

Can anyone point me to info on how to adjust these carburetors?

[DEEPNHOCK]

Here's some help...

http://www.edelbrock.com/automotive/misc/tech-center/tech-videos.shtml

https://www.youtube.com/watch?v=wR_AfQjyT-A

http://www.edelbrock.com/automotive/misc/tech-center/index.php

http://www.edelbrock.com/automotive/mc/carburetors/pdf/carb_owners_manual.pdf

http://www.edelbrock.com/automotive/mc/carburetors/pdf/carb_owners_manual.pdf

[RadioRoy]

MOTORS manuals are great, very detailed, well illustrated and helpful. There should be some info in the Studebaker shop manual also.

[345 DeSoto]

What DEEPNHOCK said...

[bensherb]

Here are a couple more, with parts and info on opperation.

http://www.thecarburetorshop.com/AFBtuningtips.htm

http://www.carburetor-parts.com/Carter-AFB-Metering-Rods-Jets_c_644.html

[altair]

There are about 150 models of AFBs, the model numbers are stamped on a boss on the top. There are carb kits for all these models the kit number will fit several models. Usually in each kit there are detailed adjustments for float level, accelerator pump travel, choke travel. These are usually set for each vehicle application and rarely need any further adjustments accept when mixing and matching carbs and vehicles. In the day most carb mechanics used small bending hickeys to achieve the correct travels, once that was done they never had to be touched again. The only adjustments that may need tweaking are the idle adjusting screws and they are very simple, turn all the way in until they touch home then back off about 1 1/2 turns. With every thing tight and no vacuum leaks, you should never have to touch it again. If a smooth idle is difficult to attain look elsewhere for any vacuum leaks firstly.
The carb itself is rarely the problem.

[DEEPNHOCK]

Trust nothing.....
I just pulled apart an almost new Edelbrock 1403 500 cfm AFB carb to clean the E-10 gook out of it.
The float adjustment was way WAY off... (and I had this carb since new)...
The choke adjustment was off.
The engine runs great now... But.....

There are about 150 models of AFBs, the model numbers are stamped on a boss on the top. There are carb kits for all these models the kit number will fit several models. Usually in each kit there are detailed adjustments for float level, accelerator pump travel, choke travel. These are usually set for each vehicle application and rarely need any further adjustments accept when mixing and matching carbs and vehicles. In the day most carb mechanics used small bending hickeys to achieve the correct travels, once that was done they never had to be touched again. The only adjustments that may need tweaking are the idle adjusting screws and they are very simple, turn all the way in until they touch home then back off about 1 1/2 turns. With every thing tight and no vacuum leaks, you should never have to touch it again. If a smooth idle is difficult to attain look elsewhere for any vacuum leaks firstly.
The carb itself is rarely the problem.

[Lou Van Anne]

Thanks everyone...always receive good advice here.

[bensherb]

There are about 150 models of AFBs, the model numbers are stamped on a boss on the top.

Actually they made 505 different versions of the AFB. But there are only a few major body vairiations and several different throttle plate bores. One major difference between AFB's is the auxillery airvalve, it's the largest variable between versions.

The correct AFB for an R1 should be a # 3506s, it's aprox 637cfm@2"hg. It has a primary throttle plate bore of 1.437" and a secondary bore of 1.690". The primary jet should be .089" and the secondary jet .077", metering rod should be .069"/.058".

Sorry, I've not had a correct secondary air valve to compare.

I currently have an AFB #3651s for a 1964 Pontiac 421/AT on my GT. It was the closest to the Stude AFB I could find, and has the correct throttle plate. I Started with the Stude size jets, but have changed to a .092 primary jet and a .071"/.058" metering rod to fatten up the primary side a bit. It's still just a tad lean. The metering rod springs make a difference too, but I can't say what springs I have since they're all black, no more color code. The secondary airvalve must be pretty close since the transition to secondaries is quite good and smooth. However, If I was being very picky I might say is was a tiny bit slow, so it's not perfect..

[altair]

I used the "150" models number to infer that there are several models of AFBs. Each model has its ident info no. stamped on a boss. If the OP wanted the info on his carb that would be the number to address as opposed to AFBs in general.