The main concern with a motor is heat. If it fails to start quickly, runs too slow for the fan to keep it cool, or is overloaded for a period of time, it will overheat. The overload protection may not act quickly enough to protect the motor, but, I've seen many 240 volt motors running on 208 volts.
If your boss insists that the motor be connected, he could very well be telling you "I told you so", in a couple years.
