AFB idle adjusting

[pishta]

I read a whole chapter on the idle circuit of a Carter AFB, and all I got from it was the more backed out the idle screw, the more air/fuel was administered into the intake. The more the idle speed screw is tightened, the less effect the idle screws have. Did I miss something? It also stated the idle restriction was "deep in the carb, fixed, and unadjustable" C'mon, I gotta be able to adjust my lean idle condition! I have no leaks,period. Any suggestions? I got a tuneable Holley, but the Carter looks better! Thanks

[coupe]

I had no probs when I put mine on, the idle mixture screws do not really work if the carb is the wrong size, ie too big. The screw adjusts the amount of emulsified air and fuel allowed into the intake at idle, not the mixture of the emulsion. That is set. I think that's what your reading means. I have never set my idle with a gas analyser, I just set it up right in the middle of when it stumbles too rich and too lean at idle. My idle is strong at a low RPM. I have a mild cam which helps.

[pishta]

Yeah, I read on, and it says if your idle is too lean, you probably got blocked fuel passages in the main casting, soak it. This was a shelved unit. Cool how they explain the reason for a richer than stock idle on a cammed engine is the exhaust diluted intake charge, due to the larger overlap of a long duration cam. Its a 600, but I have a brand new Edelbrock 750 I might use, giving up a little low end.

[LA360Dart]

Hi pishta;

This problem is something I've been fighting on a 360 that is close to stock. The (1407 Edelbrock) transition from idle to main circuit is lean. The jetting is now at .136 with 63X37 metering rod and .129 secondary and the engine is still lean. The largest jet from Edelbrock is .119. It gets hot idling (put a TQ on and driveability is back and jetting seems right). Edlebrock is working with me but I don't have much confidence that this will get better. I 've called them before and the techs are not real good from what I've seen. This carb has been on three diffrent engines and the same problem has been on all. Best of luck ! P.S. a guy at work said he had the same problem and went to a holley and problem went away

[Dr. Righteous]

HEY.....
SAME CARB (Edelbrock #1407)
SAME PROBLEM!
Mine is a freshly built 383 with a mild cam.
I can't seem to get the idle mixture right and its acting like its too lean and running hot at idle. A problem with the carb huh?
YIKES@!

[LA360Dart]

re hi

After talking to Edelbrock and going there, I talked with the head tech guy, he said that the booster may be wrong. There is a small tube that drops into the fuel well, that sets up the mixture for the idle circuit the hole is .037 for the 1407 and if is restricted the off idle circuit will not respond and will cause the engine to get hot at idle plus the mixture screws get opened so wide their inaffective, on some Chrysler's he has seen some guys have to goto .041 and larger. To get at the tube, remove primary booster and drill the hole larger( the small tube only). I'm doing this and will let you all know if problems go away. Will keep you informed.

[383ina83]

I have the same prob with mine. Just got it back together and can't seem to adjust Idle!
Idle seems fast even with screw all the way out. Timing is set@ 5 BTDC. Thats what all the books say to set it at. It's a stock 383 Hi-performance 67 model with the 915 heads. The carb is an Edlbrock 650. Is my lack of adjustment due to the fact that my carb is to small?