Quick Fuel Secondary air adjustment

[Gaz64]

Originally Posted by AC Ventura2

Hi Gary. Had to re register as AC Ventura2 to enable sign in.

Thanks for the carb info. I will check under load vacuum, by taping the gauge to the screen, but can’t drive the car as yet due to severe lockdown here. . In the meantime I’ve ordered a 4.5 and 8.5PV and a selection of primary jets no’s between 70 and 60. As they at low cost, I’m prepared to take a chance on this.
If by mixture screws you mean the four corner idles, they are all about 5/8 of a turn out from bottom. This is where I found the max vac. Any further in and it drops again.

If you mean the

I think you need some help from some exhaust gas analysis.
A wideband O2 gauge is helpful. I use a datalogger, which logs tps, map, O2, rpm.
Your mixture screws at 5/8 are close, but for me I would like to see them at 3/4 to 1 turn.
If they need to be at 5/8, the IFRs are a fraction big for your engine.

And now with lockdown happening, tuning a cobra on a roadtest is just not going to happen.

And if your "richness" is idle/low speed related, replacing main jets progressively leaner from 72 to down into possibly early 60s will not solve your issue.

Gary