If your plane is laterally balanced (and don't forget the prop is not centered on the plane, so don't balance from the prop):
Check your right thrust. You can also try a touch of left rudder mixed to zero throttle and see if that helps. It could be that the right side of your plane is slowing down more than the left side of the plane due to thrust line issues, or you have a touch of rudder trim to compensate. Your high rate elevator is a big air brake, in addition to the fact that pitching up the wing initiates a stall quicker.

Glow vs electric: Gyroscopic? spinning propeller generates a torque about the thrust line, forcing the left wing down (pilot perspective). I'm sure that does something...

And the guys are right about wings level. When I was driving around the AMA property during the NATS I was watching some of the masters/FAI guys (not sure who was on what line) from a point beyond the landing strip and far off to the side, basically so planes were flying toward me and away from me - I was amazed at how many people routinely carried their inside wing low.