ORIGINAL: Nathan King
I find both two and four strokes to run equally well inverted, provided the pilot takes the time to set everything up properly.
Exactly.
It takes a bit more care with the plumbing and/or starting proceedure, but otherwise there is almost no difference.
The tank height is important to prevent siphoning as the OP experienced, but even in cases where adjustments cannot be made, a slight change to the startup proceedure can help immensely...
e.g. less priming, and once primed immediately dropping the throttle to idle before attempting a start. The latter slows the siphoning rate either from or to the tank.