46mm pmo's

[rbutts]

I have a 1979 911sc 3.2 shortstroke,9.5 J&E pistons,964 cams,15/8 outside diameter headers and a 2 in 2 out Dansk stainless steel muffler. I installed 46mm Pmo,s with 38 venturi's,155 mains 190 air corrector,55 idle jets ,130 idle air and
F11 emulsion tubes. The promblem I'm having is when I turn out the air correction screws out even 1/8 of a turn I get a dead spot if I push on the throttle to fast.Have tried 60 idle jets and richening up the accel pumps to no avail.Turn the air correction screws back in and I get a bit of a rough idle but the dead spot almost disappears. I think I'm headed in the wrong direction, so I'm hoping somebody out there knows more than I do.Thanks for any info you might have.

Rbutts

[2.7RACER]

Are you saying the idle is set up with the air correction screws fully closed?
Turned in all the way?

Approximately how many turns out are the idle fuel mixture screws set?

Where are the idle stop screws set? 1/2 turn open, 1 turn open, more?

Are you near sea level?

I'm thinking the idle was set up with the idle stop screws 1 turn or more open.

[rbutts]

I'have solved my problem. I decided to turn the mixture screws one turn farther out and see if I could now adjust the idle air screws.Like magic I can now adjust them.The mixture screws are now about 3 turns out instead of 2-2 1/4. I was running to lean to mess with air corection screws.

Rbutts

[2.7RACER]

You may still be lean at rpm's from idle to 2500 rpms where the mains begin to take over.
By going to 60 idle jets you'll need to turn the idle fuel mixture screws in from the present 3 turns out to get a proper idle.
This will richen the lower rpms.
If you are happy with the present set up, enjoy.

[Wayne 962]

Neat setup. I can't give you any specific recommendations, except that you pick up an LM1 if you don't already have one. It's really nearly impossible to tune these carbs accurately without knowing what the mixture is, coming out of the exhaust. I use mine to tune my carbs - it's a difficult process even with the LM1 - without it, it's like shooting blind...

-Wayne

[rbutts]

Thanks everyone,I put#60 low speed jets in and left the mixture screws at 3 turns and no more hesitation and flat spot. I will get out the syncrometers and fine tune each barrel later. So far so good.

Rbutts

[2.7RACER]

Way to go!