1978 Ski-Doo Shop Manual, Page 323Get this manual
SECTION 05 SUB-SECTION 04, (ELECTRIC STARTER)
Field windings and brushes
Test the field winding for open circuit using growler test probesPlace one test probe on the negative brush and the other test probe on the yokeIf growler lamp does not turn on, the field winding has an open-circuitThe yoke has to be repaired or replaced
Test for ground circuit in the armature using growler test probesCheck between armature core and the commutator barsIf growler lamp turns on, bars are grounded
Test armature for shorted windings using growlerWhen the armature is rotated in the growler with steel strip held above it, the strip will vibrate over that area of the armature which has short circuited