Hello Everyone.

I attached a tuned pipe and a long header to my Mitsubishi 33cc conversion with very good results. (7,800 RPM´s at 2,400 meters osl with a 18x6 prop)

Anyhow I´m having troubles, I set the needles and get very good RPM´s on the floor and when taking off.

But at the first minute of flying the engine began acting as if it was flooded, even closing the high needle

The problem comes even worst If I Invert the plane it lowers down a lot the RPM´s getting totally flooded and getting back to normal when getting the airplane back to a normal flying position.

The engine is mounted with the piston up

Could this be a problem with the membrane of the carb being old and not flexible enought which is allowing to much gas to the carb when inverted?

In advance thank you very much for your help.