Are you using pressure from the pipe/ mousse can? I had a recent experience with a PIcco 40 that I made a mousse can pipe for. It would not run (couldnt get it lean enough) with pressure line to the tank from the mousse can, but ran fine without it!

If you drill the airbleed slightly, it will pose no problem, as you can allways turn in the screw if its too much air entering.

AJC