I recently got a Phantom 2, and everything worked fine for the first few flights. Then I just tried it, and on start up one of the props is not spinning properly - it spins for a few seconds, stops, and then starts up again without ever reaching the speed of the other 3 props. What's odd is that if I run it without the props attached, it doesn't happen and the motor appears to run fine, at the same speed as other 3 and without stopping. I've tried swapping the props but it makes no difference. Has anyone got any suggestions as to what I could try to resolve the issue?