Sounds like the ESC is overheating and shutting off to protect its self. Once it cools off it turns back on. On the v3.1 the fan should be on all the time if it is plugged in. Even when the fan is unplugged it shouldn't overheat in 2 mins.

What turn motor are you using?

There are a couple typical causes for this. You could be way over geared or under geared. Over gearing will usually overheat the motor first. Under gearing will usually overheat the esc.

You could have your pinion gear to spur mesh to tight. That will cause a lot of resistance in the drive train and over heat things really fast. There could also be some binding in the drive train that is causing a lot of rolling resistance.

While poor soldering could cause overheating at the solder joint I doubt it is what is causing your thermal overheating issue.

Make sure the fan is plugged in all the way. If it starts and then stops give it a little push and see if that gets it going.

Something is causing your overheating issue. Its hard to say exactly but it is most likely a resistance issue. Check the pinion/spur gear mesh. If you just replaced the bearings that would be my first guess. Also the motor should turn fairly freely when not connected. If it doesnt there could be a bad bearing or rotor in the motor.