Axi motors 'pulsing'

[Jetstuff]

Building up heavy lift Quadcopter.....I have some Axi 2814/22 motors, running on 4 cell 5000mAH Lipoly with Hobbywing 40Amp speed controllers directly wired (no connectors).
Just running one motor direct to the receiver for rotation direction and ESC tests......I have selected Medium timing on the ESC....The motor runs OK up to about 1/2 throttle , but then ‘pulses’ violently above 1/2 throttle (using a 13 x 6.5” APC electric propellor). , I have tried Low timing with similar results and High timing is much worse....it's OK on 3 cells........... HELP please!

 

[Jetstuff]

To answer my own question.....it's the ESC's...I've discovered that even ESC's that look identical externally, are different internally....some match the Axi motors.....some don't....probably depends upon which MOSFETS etc, were to hand at the time of manufacture........

 

[DucktileMedia]

I had something similar with my Tiger motors and it turned out to be a bad phase on one of the esc's. What was hard to fiure out was that it would sometimes start ok, but after running for 10 seconds, I would stop and then upon restarting it would pulse, or bounce back and forth. essentially it was running on 2 phases.