Car in bits again...
AO Silver Member
Join Date: Feb 2007
Location: Hampshire, UK
Not sure a repair kit would contain a mixture control screw - for later carbs these screws are tamper-proofed. I guess a call to a carb specialist would solve that problem, but I do recall buying a pair of 40IDF service kits and there were no mixture control screws, or jets of any description in them.
The air bypass screw should not be fully home. I adjusted all of my air bypass screws out 2.5 turns from fully home, which I think is the recommended starting point for tuning. If you have the individual vacuum guages set up on all 4 monitor points you can adjust the bypass airflow to smooth out the idle, but there is unlikely to be any major variation in airflow to each cylinder unless you have other problems. So a nominal setting on all 4 should be good enough.
When I took my engine out of the box I found someone had messed about with all of my bypass screws. The engine wouldn't idle worth a damn, and that was all that was wrong - one screw had one turn on it, another had 5... you get the picture.
Alfanauts are GO!!!