1990 Johnson Evinrude "ES" 60 thru 70 Service Manual, P/N 507873, Page 228Get this manual
Cleaning and Inspection 1Inspect the brushes; replace if one-half worn, damaged, or cracked Replace brush springs, if weak2Clean commutator with 300 grade emery clothIf commutator surface is unevenly worn or pitted, turn on lathe Remove any trace of oil or metal dust from commutator3 Check the armature on growler for shorted turns Check armature for grounding by using test light or meterInspect armature insulation for indications of overheating or damaged windings Clean off any deposits of carbon or foreign matter which may contribute to later failure of the windings
4 Check permanent magnetsMagnets should strongly attract any steel or iron object held inside the frameWeak magnets wi" cause excessive rpm on Load Current Draw, Electric Starter test