Over the past year I've broken in 8-9 new engines, all inverted.

Other than the noted siphoning issues, and slightly more intolerant needle settings, they run w/o problems.

This includes OS, Evolution, Supertiger, Magnum GMS & Tower Hobbies engines ranging from 2 stroke .46's through BGX-1's and four stroke 1.80's.

None run with glow assist, though I had purchased an on board ignitor to handle my Evolution 1.00NX.

My Evolution 1.00NX was the most intolerant of the inverted position, but I'm glad I mounted it that way. Mounting it inverted and my frustrations with it this way resulted in my eventual replacement of the carb, which cured all of the problems I had with the engine.

It ran fine inverted once I resolved the problem it really had.. I never did install the on board ignitor.

Better that I find this out on the ground, rather than in the air with the plane inverted or on it's side.