Excellent response sir!
Thx so much!
I will try OS engines then.
I bought a .50 Thunder Tiger last month and after 2 mins or more the barrel in carburetor alway jam and i must disconnect the hose comming in carb to stop the engine.
I have 2 .39 Thunder Tiger too and after same time they seems to loose power!
One has no more than one hour of runnuing time and the other a few hours.

Great thx!
Steff.