Hi wsmaley,

i used an inverted two stroke most of last year. Was a lot of trouble untill i leaned out the idle enough that it didn't load up. The flame out on climb out kinda sounds like you are pushing the high speed needle a little too lean. if you mean climb out on take off this is likely to be because once you pick up air speed, the prop spins a bit faster and the air enters the carb a little faster than when adjusting on the ground, so it leans out. If you mean climb out as in you are zooming along and you point the nose up and it dies, the tank might be too far back or too long and you are pushing the needle too lean for that kind of flying.

Tank height is really quite important. If you have it right, the engine will run the same when you fly inverted. Some two strokes seem to be more sensitive to tank height than ohers. The ones i have had most trouble with is the Tower 46 and others that have the big expansion muffler without baffles. They don't produce much pressure for the tank. Just installed a Macs muffler on one last week. didn't gain or loose any RPM, but I had to turn the high speed needle in about a full turn, to compensate for the increased tank pressure. (?) Higher tank pressure = consistent fuel flow. so far it seems to have done the trick.

I have an inverted 4 stroke in an aresti, works Fine, but my guess is it is vulverable to the same problems as a 2 stroke.
one advantage of the four stroker is the plug enters the the cylinder at a 45 degree angle at the side of the head, instead of straight up from the bottom of a funnel (dome of head).

my two cents worth, refunds available on request.

best of luck.

Shmo