P3S yaws CCW on full thrust

[GNS Servo]

I noticed the past few flight that as I lift the craft with full thrust it starts to turn CCW. When i stop, the craft turns violently to the forward direction. I have tried several different props (new stock and cheap ones from China) and it acts the same. I am suspecting a motor might be going bad, but I don't know which one.

Also, I have also received an error several times about "max motor speed reached". But I don't know which one(s).


Any ideas?

 

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The props have a 4-digit number on them, make sure they are all the same.