1. Check for an open in the starter winding.
Using an ohmmeter, measure the resistance between the terminals of the stator winding coils.
If the resistance tends to infinity, i.e. circuit is open, replace the stator.
2. Check if the stator winding is shorted to "mass".
Using an ohmmeter, measure the resistance between the stator housing and the stator coil leads.
If the resistance is "0", i.e. circuit is shorted, replace the stator.