Chrysler 100, 115 and 140 HP Outboard Motors Service Manual, OB 3439, Page 116Get this manual
BPlace contact fingers of meter test cable across any two commutator bars at side of commutatorCAdjust voltage control until needle hits highest reading DTest each commutator bar with the bar next to it until all bars have checkedA zero reading shows an open circuit in pair of bars BrushesReplace brushes if any are half worn, damaged or crackedTo replace brushes, the commutator end cap assembly must be replacedFigure 11 1Check brush spring tension Replace springs if tension is less than (40 ounces) maximum Insulated Terminal Ground TestEquipment: Ohmmeter (R Scale) or 2938-1 Circuit Tracer1Place one tester lead on insulated terminal (outside of motor frame)2Place second tester lead on motor frame, meter should indicate (infinity), tester should "not" lightA meter reading or tester lighting indicates defective ground Figure 12Field Winding Ground TestEquipment: Ohmmeter (R Scale) or 2938-1 Circuit Tracer