Hi Dave,

I have both a 63FZ and the 63S. The 63S is a real beauty - runs and tunes easily right out of the box. Both engines are new.

Unfortunately, I've been having problems getting the 63FZ to run consistently.

I have managed to tune for max rpm and richen out the main needle by 2-4 clicks for flight. It has a decent transition from idle to WOT and maintain a pretty solid idle.

The problem is that it doesn't maintain this setting and seems to lean out(?) in flight. It would start to loose power and somewhat regain composure after I back the throttle to half, but would usually be forced to land soon after.

I started with a 12.5 x 6 prop and have since changed to a lower loading prop (12 x 5) to help with any temperature related issues. Problem still persists. Fuel is Cool Power 15% Heli (tried Cool Power 30% Heli, not much improvement) and OS F plug. Max rpm with the 12 x 5 is 11,200.

Lately, the engine has been having some problems transistioning from idle to WOT - sometimes taking 10 secs or so to get to WOT. I have tried leaning and richening the regulator to no avail.

I have replaced the diaphram - no change in behaviour.

I would appreciate any help you can offer.

TIA,

Chen

It needs to be returned to someone for service. Probably to Japan judging from your location.

Thanks Dave, will do.

Good Flying!