I have the Superstar .40 trainer ( O.S. Engine) and plan on taking it up tomorrow, and haven't been able to fly it in about a week so I was feeling ancy and decided to crank it up last night...

Fired on the first try then slowly died to idle, and the prop nut came off, so i re-tighened it and put the spinner back on. I had my friend holding the plane from moving while I cranked it and operated the controls, well, I put the glow igniter back on and flipped it over again, and it fired, and started to die, it was at this moment that my friend and I noticed the prop was blowing air FORWARD not backwards like normal, suggesting that the engine was running in reverse. This lasted for about 2 seconds, and then a small kick was felt and it began blasting air backwards like normal again. It's run fine since

The only thing I can think is that it might have had to much pressure when I flipped it, but it still managed to fire, but only when the piston was TDC and pushed it in reverse. Technically I can think of no reason for it to not function like this, but found it very strange..

Any thoughts??

It's very common if it's a new engine and have had happen to me a few times but once the engine wears in it seems to go away.

Okay, so we aren't insane

2st will run both ways .Sound.s like you are starting by hand . try starting in reverce. Some times you meet compression and it fires in reverse causing the the motor to run in reverse. Make prope is pulled through. Chicken stick or bloody finger your choice.

Nah i use the back end of a screwdriver, I'm not brave enough to stick my fingers in there

It's just a little bit over primed so almost flooded. Most engines will run backwards for a while like this but not at a whole lot of revs
The kick you felt was when it'd burnt up the extra fuel and suddenly reversed direction. Sometimes you can help them kick back to the right direction by suddenly opening the carb a little. The cure is to begin reducing the amount of prime you're giving it until it'll start the right way first time every time.

I have got an OS 60 that most of the time I start it with a quick flick backward. Especially after I have run it a bit and if it quites for some reason I put on the glow starter and give it a flick backward and it starts right up turning the right direction. I have seen others do the same thing also.