Hi there :-) The 10 seconds is to let the fuel vaporise a little so it fires up more easely, that type of engine is just not easy to start in cold weather...
the roll yaw should have been fixed by adjusting the fixed rudder trim, it was indeed looking a bit to the wrong direction ...
it was the rudder since if it's wrongly trimmed it goes into a roll...
I was a bit worried about the huge amount of white smoke and smell that came out of the engine compartment, but most blokes above seems to be ok with that carburator backfiring...
wsmempson and ShyTorque are just paid members of my fan group, it makes PPrune loads of fun!