brake,
It should run for normal time when you flip it. Espeacially after 10 minutes. It was probably that you didn't have a full tank or something. On mine, if i am going backwards with the prop, i can make it go forward by just throttling up, and then when it is about to die go back down. What this does is make the engine almost stop, then gives it gas to go the right way. It works good. I can't tell you if it is good or bad for the engine. if that method doesn't work, i can put my starter on the spinner to make it stop and when it slows down it kicks in.

Hope this helps
Chad