Yes, it should crank. Does the starter turn if you only push on the contact button under the shift lever? If not, make sure your connections are good. If yes, does the starter turn without turning the engine when you try a normal start? If yes, the starter drive may be slipping and needs to be replaced. If no, maybe the starter needs to be repaired. You can look at the motor brushes and commutator if you take off the inspection band from the front of the starter. The commutator should be clean and shiney. If it isn't, the starter should be repaired.
Six or 12 volts are alright, but don't leave the ignition wire connected when the engine is not running if you are using 12 volts.
Harvester
