I bought a hobbico superstar 40 select. it is my first and only plane. everything was already mounted. I cant gett the engine started. i followed the directions, but nothing seems to work. when i prime the engine the gas comes out if the tank, through the needle valve, into the carborator, and to the engine. but after i stop turning the propellor the gas flows back into the tank. i have experimented with different nrrdle valve settings, throttle settings, and have changed all of the tubing. but nothing seemed to work. i even got a friends engine and mounted it and the same thing happened.

P.S.-in a different plane my friend's engine works fine