In addition:

- The ESC may have not "learned" the full range of the transmitters throttle. You may have to "teach" it the full range again.

- Check to see that the motor and prop turn freely, the motor should not heat up when you run it full throttle for a few minutes.

- Please provide the URL for the replacement battery pack you purchased.

- Most ohm meters are useless to tell you the state of the battery pack.

- The 400 brushless motor and ESC provided is normally a very good match to the plane, so something is amiss.