George: I just finished another short run, and I used your directions concerning the balance between needle and compression. I ended up with what I think is a higher RPM, a nice growling sound overlain by a kind of cyclical sputter. Will try another one-minute run and see if I can get it smoothed out in accordance with your clarification. Using the 8x6 prop.
Ray: I did a pressure test on the needle valve before the run, and air starts to blow by at a quarter out (lock nut removed). Who knows!?
Thanks.
Dave...