I am necrobumping this thread up due to a question. Hopefully some of the fellas that contributed to this thread are still around.

I recently acquired a near-new GMS .47 engine (non remote needle version) that I'm trying to get running good. I've read the whole thread with great interest and have a question in regard to the idle needle/spraybar interference issue. I already fixed the fuel inlet misalignment problem, but now I need to deal with the idle needle and spraybar interference problem. As has been noted, if the idle needle is set for good idle and transition, the high speed operation runs lean and no amount of needle adjustment on the high end will richen it up enough without having the idle needle set way too rich. Is it better to shorten the spraybar or the idle mixture needle and how much needs to be taken off to obtain good results? FWIW, I ran the engine with an Irvine carb and got good idle and transition, but the smaller throat carb robbed a lot of power from the engine - at least 2,000rpm. So I'm very motivated to fix the GMS carb. I do not have the GMS/Tower muffler, but I do have a red Jettstream muffler.

Thanks in advance.