How to change android primary google account
I believe I had a similar problem.
I just bought the Moto X on Verizon.  I linked 3 Google accounts to this phone (including my wife's to sync our calendars.)
The phone chose my wife's account as the primary so when I sent text messages they would be sent from my wife's Google account.
SOLUTION:
I went into the Google+ account app, logged out of her account and then the phone asked me which one to log into.
Problem solved to change my primary account without factory reset.