The schematic may not be clear. It only shows the wiring that runs from the power source to the motor starter (MS 25), the thermal overload (KN 12), lockout (or reset button), the switch, and then the motor wiring panel. I do not know the internal connections for the various components. I have searched the manufacturers information but have not found the diagrams.
It seems to me that both 120 legs are connected to the lockout from poles 5 and 13 on LN 12. (The connections for the lockout are not as drawn but actually are wires from poles 5 and 13 attached to one side and the wire on the other side going to the main switch.) The switch when closed then feeds the power through pole 14 on LN 12 and out through 4 and 6 to the motor wiring panel. But this seems incorrect because the switch would only activate a single leg (one wire) running to 14. Then again, maybe the internal wiring of LN 12 activates both 4 and 6 when power is received through pole 14.
Here are 2 more pictures of the wiring for the lockout and main switch
Wiring for switch.jpg
and the motor wiring panel.
motor wiring.jpg
I will test for continuity and power through the components and see if I can add information. For now, it seems very likely that the motor is only getting one leg of power because of the reduced output and the slow start up.
Thanks again for the input.
David