912UL intermittent rough running
Hi guys,
I have a 912 UL that runs rough while flying around. It only does it here & there, it's not rough all the time or at certain rpms. It seems to come & go. I can vary the rpms & get it back to running smooth. It runs smooth as butter at idle & during run up on the ground. It only seems to happen after flying for 5 mins or longer. I've recently replaced the carb boots, synced the carbs, checked the jets & needle positions. New fuel filter, oil change.
Could the carb floats be giving me this intermittent rough running issue........? When it does it, it's more of a "shutter" than a simple vibration. When it "shutters" it loses rpms & doesn't want to increase rpms if I give it more throttle. If I back the throttle off & then reapply throttle it will go back up. When I can get it past the shutter it still runs nice & smooth in flight until the shutter comes back. I'm puzzled by this problem.
Any help would be much appreciated.
Jesse