Ok, picked up a saito 91 4-stroke today....its going in my 4*60 that im building...

My first time with a new engine (my other plane is a nexstar, comes already broken in)

So i made up a nice stand to break it in on....very stable, nice setup...

Due to a wrong recommendation from the guy at my LHS, the spinner doesnt fit on (the cone, the backplate fits and holds well, just the cone doesnt fit over the 12-8 prop)

Since i didnt have the cone on, i used a chicken stick...

After a while of adjusting the height of the gas tank (too low, not holding its prime, too high it drips out of the carb...fun) i got it straight, got it to hold its prime, now im happy, checked glow plug and ignitor, good....ok, 3...2...1....spin....POP.....and prop comes loose....

Ok, maybe flooded, did that once with my nexstar (with the electric starter, just spun the prop off) ... took off glow plug, spun it up a few times, even inverted it to make sure...

Put everything back together....spin it a few times, spins good....no binding out of the usual, spins through a few revolutions without tough binding....

Put glow ignitor back on, spin with the chiken stick...it tried to start but was backwards...got a little combustion, but only made just a little bit of a turn....spin it again...loud POP

again, prop loose....put prop back on tight...check for flooding, nothing....

Im not going to try it with the chicken stick again....going back to LHS tommorrow and getting a good spinner...and will try it with the electric starter...

Anyone have an idea what the pop was....im not sure if it was the prop spinning back and hitting my chicken stick....or if it was something bad...

Im kinda nervous about hurting this engine in any way....not cheap....but i cant see what im doing do any damage on a motor thats supposed to last a while...im not (As far as i see) doing anything rough or out of the ordinary....

Hope i get some replies, will be a coupld of days before i try again, my dad is headed out of town for a couple of days, and i dont want to start it up alone....just incase something bad happens....

thanks
Joshua