I saw on here a few days back a thread on three motors sunning fine and one stuttering.... I have that issue on my new kit, anyone remember what the final outcome was? brand new motor already toasted?
sounds like one of the three motor wires is broke, usually is at the connector. if you go to the esc on said motor and slide the three connectors out, you'll probably appear to break a wire off one, it's usually the heat shrink still holding it all together but the wire itself broken causing it to spin aimlessly with just 2
after attaching to another esc it stuttered a bit then ran, back on its original esc and it runs... 20 starts back to back? cured or failure waiting to happen lol
Still sounds like a bad wire, be careful. if it was mine, i'd resolder the three wires just so that was eliminated from my mind while i flew it. kinda common thing that happens with these little motors, thin wire