I have one prop on a Phantom 4 that when I start them up theres one that sometimes doesnt start up but just sits there kind of jerking like its slipping, was thinking its the motor giving issues, Ive turned it by hand and with the prop on and with the prop off seems smooth dont notice any difference from the other ones but yet sometimes it will start up normally and next time its sits there like its stripped, anyone have any other ideas as to why its doing this before I got out and spend money on a new motor.....the Bird is like new very few hous on it at all, kind of weird that the motor would be bad already, anyone have any ideas?