AFR - 14.7 or other?????

[CUDA JAS]

I know and AFR of 14.7 is the target, byt my cuda seems to idle best (in D) at about 13.5.

It still smells a littel rich at this AFR, but the idle is crisp and smooth.  Any closer to 14.7 (and I mean a 1/16th of a turn of the idle mix screws) and the idle is choppy and the AFR meter jumps around from 13.7 to almost 15, almost like there is a miss.

SO, I have never actualy got to the 14.7 mark.  IS this normal, will an engine find the mixture it likes, or shoudl I be trying to get to 14.7.

Keep in mind I am running a holley 750 vac secondary with out all the bells and whistles (i.e, non adjustable air bleeds etc).

Thansk,

Jason

[Chryco Psycho]

@ 13.5 you are probably where you need to be , atomization of the fuel at idle is poor with a carb so some may be going through unburnt , if iti idles bast at 13.5 I would leave it there .

[brads70]

I suspect with messing with the air bleeds you might clean it up further? Tough to do on a carb that doesn't have removeable bleeds though.  I found by drilling the idle air bleeds slightly bigger I got to the 14.5-14.7 at idle. But every engine is different I would assume?

[73restomod]

Hmmm, 13.5 is the average across your cylinders, some may be leaner or rich than others due to manifold distribution. I say go with what makes it happiest.

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[cudabob496]

what is it when you are cruising, and when you smash the throttle?