Remove the prop and check for fish line wrapped tightly around the shaft. With the prop installed, turn the prop by hand (power off of course). The prop should turn relatively easy but may have a slight jerkiness to it. That's normal. If it seems to turn hard, then the bearings have tightened up and repair is required. But before doing any of this, make sure you are using a good battery. Just because you charged it does not mean it's a good battery. A battery must "hold" a charge and all cells must be doing their job for proper motor operation. A good test would be to put a voltmeter on the battery while you run the motor. If the meter is not showing 12 - 12,6 volts under load you have a bad battery. You could also use your car battery or have the current battery load tested at the local auto store -- usually for free.