I'm not sure if you are challenging this method of starting larger motors or not. If you add voltage to any motor and leave the winding or poles as they are then you will add both speed and power (torque). Sure, if you add more volts from a battery that has not got the capacity or current discharge rate to supply the load then you will just turn faster for a moment and stall when touching the spinner. I am assuming everyone knows to use 7 Ah or better batteries for starters.

The fact is my starter will not turn over my 120 2 stroke on 12v. Series in another 6v 7Ah battery and it turns it over very well.