So to be SPECIFIC, which we really really need here, "then stops" means with foot pushing on pedal, starter turns motor over a few revolutions, then still pressing on pedal, starter no longer operates? All is dead? no sound and no starter trying to rotate motor?
Do you have a multimeter? If so, set to DC volts and place probes on pos and neg posts of battery and report reading. (not on the cable clamps). Next see if starter spins by hand operating the button on top of starter.
