Hi all,

I'm a bit puzzled about the idle behaviour of my 91FZ. Main needle setting is okay at the top end. Set the idle per advice of running at full throttle, then idle, and if rpm drops slowly after a second or so, too rich, if speeds up then too lean. My issues are: i) transition - lags a bit as I advance from idle to full if it's been idling a bit like it's too rich, but okay if I've been using the throttle (like in flight, up, down, up, down) - ii) if I leave it on idle for too long, it just quits (idle too low? too rich?), and - iii) - here's the really weird one...sometimes (like 1 flight out of 3), power is great on takeoff, but after a procedure turn and maybe the first turnaround, when I advance throttle to full, the engine burples along happily at half throttle power setting only! When this happens, I land, and refuel, and restart, only to find everything is fine again. So I take off and the next flight is great! How come? I didn't do anything. I checked the throttle linkage, it's fine. Fuel lines seem fine too, though I haven't replaced them yet. (Expensive!).

Any thoughts?

Cheers,
Ken