MMM, I don't think that you are looking at the same one.. This set screw is under a tamper-proof cap on the very rear end of the AFC housing. You have to get the tamper screw out and then you can take the little tin cover off. If you look here, its just under the "Indiana" Printing.. You can see a screw and lock nut. On my pump its a smaller diameter screw and uses a small hex key.

 

Lil Dog,do you have a pic of the cam plate and arm cutaway

 

Thanks lil dog. I was indeed thinking of a different screw.

 

The theory of tuning by AFC is to limit fueling at low boost. This is depicted in the attached photo. AFC foot limits the governor lever travel long before it strikes the fuel plate. The other goal is to have higher boost push the AFC foot slightly past the fuel plate. That's why we slide the housing forward on the slots...
I like to set the no boost screw only a turn or two in. Then it acts as the zero boost stop instead of the big washer holding the diaphragm slamming against the housing.

Piers gave me my first education on tuning by AFC.
Here's a couple methods to help limit smoke. You can leave the AFC full forward and dial back the starwheel a couple turns to put more resistance against the diaphragm.
Another is position the AFC about ¾ forward in the slots and leave the starwheel forward. This required a little modification inside the housing either by grinding off some casting or changing out the cup washer on the backside of the rubber diaphragm or the foot travel may be less than the fuel plate.

If you mount the AFC housing at an angle it may hang up against the fuel plate and prevent full fueling, too.

-John
edit: re-organized the wording

 

Can the "smoke screw" affect top end fueling at all?

Thanks!
Garrett

 

No
Only if you mess with the wrong screws and jam up the mechanism.

 

I have had "choppy" performance where the power seemed to come on in spurts. I found that in my haste to adjust the plate I got the AFC housing slightly cocked and the AFC cam was riding on the fuel plate causing it to get bound up.

I will have to spend some more time on fine adjustments. Just for the books, #10 full forward, AFC is full foward, Starwheel up 7 clicks from bottom(loose) and zero stop at about 3 turns in.

Thanks for some other adjustment ideas John

 

I had 3 afc springs off VE pumps and 1 was half as thick, so i installed it on one of my p pumps and it was a huge diffrence off the line