Is this your Carb?
http://www.pjmotorsports.com/Jets%20Pics/expvm29.gif
If so the item on the bottom is the pilot jet and the angled screw/needle is a pilot air screw (2.5 turns out from lightly seated to start with)
Are you certain that the jets are clean and the carb passages are clean. After much soaking and with the aid of an ultrasonic cleaner I still found I had a jet the needed prodding with a wire to clean it. I also had a passage that I had to introduce cleaner with a needle to reach the clog. I could only see it with a magnifying loop.
Good Luck
Glenn