1997+ Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-826148R2, Page 92Get this manual
ARMATURE TEST FOR GROUND 1Set ohmmeter to (R scale)Place one lead of ohmmeter on armature core (or shaft) and other lead on commutator, as shown2If meter indicates continuity, armature is grounded and must be replaced TESTING NEGATIVE BRUSHES FOR GROUND Set ohmmeter to (R scale)Place one lead of ohmmeter on the negative brush and the other lead on the end cap (bare metal)If the meter indicates NO continuity, replace the negative brushRepeat this procedure on the other negative brush