Hello ! Ok I crashed my phantom vision 2. 2 blades needed to be replaced as they broke and one came of the motor. that specific motor doesn't function well anymore. It does spin.. but not at full speed and it feels like there is resistance. it also heats up very quickly. I dis assembled it and there doesn't seem to be any core damage. i notice there is a tiny black "screw" on the top.. that seems to work with a tiny allan key (i don't have one that size). does that play any role? if I tighten it will it make the rotor work better? thank you !