[Formerly Steve Wilkinson]

I'm assuming you have a good Synchroscope? Can't imagine what could be wrong, if you use the old screw-in-until-it runs-rough, then back-out-till-it-picks-up technique on each cylinder, starting with the secondary jets set at a reasonable and uniform point, like 2.5 turns out. A few other details of course, but I assume you know them if you've done it before successfully. Unless there's something wrong or dirty--not unlikely--internally.

Stephan