Well that did it. I backed out the low speed needle for some room to work with. Spent a few minutes with a nail file on the end of the spray bar. Did a back flush with some fuel to clean up. Went through the tune up procedure. Yay! Engine now has a good idle and transition to WOT with a responsive high speed needle valve. It's so easy it can be done at the field. (If you have a nail file handy)