Are you using NIMH cells or alkaline like Duracell or energiser..
If your using the NIMH cells note that the power on lamp on the transmitter should always be amber,or yellow..at no point with the NIMH cells in should it be green.
.Simply because the NIMH cell's are rated at 1.2 volt were as Alkalis are rated at 1.5 volt..12 volt NIMH and 15volt on alkaline cells..The reason I mention this is because my transmitter's 5 volt regulator (7805) broke clear ,poor soldering.. and gave me piles of grief..the transmitter lamp was green with NIMH cells.after the fix it went amber..
Now..You have done everything with the transmitter physically to get the motor to run ..The problem is..your doing whats required but the software is giving you the gears..From what your telling me the transmitter is not calibrated properly. what you physically input is not what the software is is seeing and telling the ESC..My guess is its a brushless setup.
I would do two things
A: get hobby king on the horn and get their tech service ,hopefully a warranty repair,,but don't hold your breath
B: crack the transmitter open and with a 10x to 20x magnifying lens..start going over the board to find something as simple as a cold solder joint,If you find carbon around any part ,hopefully it can be identified, and replaced,if not your pretty much beat.. I have no idea how to study the data stream for faults,
Sorry about your luck but the good news is ,most of what hapens to these radio's is a result of poor quality control..once they are setup and running ..the unit is bullet proof reliable.