1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 261Get this manual
2Lift motor from end capUse care not to drop armature CHECKING AND CLEANING COMMUTATOR 1If commutator is worn, it may be turned on an armature conditioner or lathe2Clean commutator with "OO" sandpaperaCommutator
Field Tests
IMPORTANT: Commutator end of armature must be installed in brushes when performing the following testsOhmmeter Leads Between 51349End CapArmature Green and Blue Motor Wires Green and Black Motor Wires Blue and Black Motor Wires Black Motor Wire, and Frame (Motor Housing) Green Motor Wire, and Frame Blue Motor Wire, and Frame Resistance (Ohms) No Continuity No Continuity No Continuity Scale Reading (x Full Continuity (R 1) Full Continuity (R 1) Full Continuity (R 1) No Continuity (R 1) No Continuity (R 1) No Continuity (R 1) )