hello Guys,

thanks for yor advise:
-I have used new byron 10/20 fuel (runs great on my saito 100 and LS40)
-fuel tank 8oz
-plugs used OS #8 and Fox with idle bar
-prop used was 10x6 and 11x5
-fuel line to carb were tested with and without inline filter (minimum fuel line length without filter) same result
-breake in as recommended by OS: full throttle and needlevalve adjustment every 10 sec from 4stroke mode to 2 stroke mode
-tank is toataly wrapped in rubber foem. No foaming observed.
-fuelline was bubblefree.
-at idle and nose up... after about 3-6 sec engine dies.

talked to OS service and was told to send engine in for inspection. Will be on a business trip the next two week. As soon as I know whats wrong I let you Know.... any other ideas are more than welcome.

Thanks for your time and help so far I really do appreciate that.

JF