sounds like the idle air screws are in too far
yep the flat spot. I've attached George Willets weber tuning doc--hope he doesn't mind. when all is right and you have to run the idle circuit screws out that far then determine what jets you have and go up until it tunes correctly and the flat spot is gone.Is that also a factor of the idle jets being too small?
I agree if he has normal range 2L jets and has to run the idle air screws out 4 turns (or 8 flats) then he has other problems. I believe I would check the jets and the fuel level first. the idle screws out and a huge flat spot reads like the jets are too small--but you never know until you lookI generally agree with the above posts - to a limit. The normal idle jets for these carbs on a 2L Alfa engine are 50F8. I like to run a little lean and I prefer 50F11. But if he has these jets and he still has the problem and it is alleviated by screwing out the idle jets, then I say he has either an air leak or low float level. I don't agree that putting in bigger idle jets is the solution. It may mask the symptoms but not cure the problem. Say he has an air leak and he makes his engine run better by installing 55F8's. Then the leak gets bigger. What should he then do, install 55F9's?
A page from centerline (I don' think Joe will mind) showing how you engine came timed from the factory. http://www.centerlinealfa.com/tips/images/p51.pdfEd, how do you tell how many degrees you're at when the timing marks are M P F?