Motor making cracking noise?

Anyone get this noise or know what’s wrong?
I have two flipsky 75100 which give this cracking noise if I do anything more than maybe 1/3 throttle. I have to ease my way up to speed but it’s still weak and maybe 1/3 the torque possible and sucks on hills
The motor doesn’t get irregularly warmer.

The whirring noise is something else. (Imbalanced motor with loose shaft).