I just saw Fhuber comment about the shape the needle should have and I guess I have this problem.
My evo46 is still driving me crazy, even after I sent and received it back from Horizon where they said they replaced the carb.
The engine looks also running rich, bad transition from idle to high speed and the worst of all, very randon behavior.
I adjust the idle needle for a good idle and transition and high speed needle for good high and when I stop at the runway to take off, it just don't respond from idle to high anymore![:@]
I saw that by looking inside the carb when it is fully open, the needle that is the left part and that moves in and out of a hole in the right part ends abruptly.
See picture below and let me know if I'm in trouble!

Nilo