"Yes, it turned out to be the screws 100% positive. I am glad to have finally resolved this issue, thank you so much for your input!"

"Okay so I just tried all the suggestions and it turns out it was the screws (too long). I just plugged in the one working motor into ESCs of motors that we're not spinning properly and it spun perfectly. I then found some shorter screws I had lying…"

"Okay I will definitely try that. And if the motor does spin that means the other motors are busted correct?"

"Dang it, haha do you know what is a good length for motor screws? There were some that came with each motor, however, they were not long enough to screw into the frame so that is why I used longer ones."

"I'm sorry I should have specified.

I have had the motors attached to the 50A ESCs before and they were spinning fine (which I assume means the ESCs are calibrated). However, only recently I have had this problem where only one motor spins and the…"

"Yes that seems to be very similar to my issue. So as to your understanding what could be the cause of this on my quad? The screws or ESCs?"

"Both of your suggestions sound logical, I am not sure whether to bank on the ESCs as a problem or the screws in the motors as a problem.

However, one other problem I have had is that I had been trying to use 30A ESCs before with these same motors…"

"They are about half inch long. Could the windings on those motors be that fragile?"

"I moved the throttle up a little in the beginning and then moved it up more towards full throttle after that. And as for the ESCs, what is the exact problem that would be caused by overpowering the motors? And yes ESCs are calibrated."

"Here's a Dropbox link to a video of the problem: https://www.dropbox.com/s/qdjpxz9vv3fndn4/20140709_222100.mp4"

"My point that I was trying to get across was that I have two seperate quads, one that uses a 4s battery and what that uses a 3s with the motors rated accordingly depending on the battery used. I have used an arduino with my quad that uses a 4s…"