1993 Johnson Evinrude "ET" 90 degrees CV Service Manual, P/N 508285, Page 241Get this manual
Cleaning and Inspection 1Inspect the brushes; replace if one-half worn, damaged, or crackedReplace brush springs, if weak2Clean commutator with 300 grade emery clothIf commutator surface is unevenly worn or pitted, turn on latheRemove any trace of oil or metal dust from commutator 1sl16l 3Check the armature on growler for shorted turnsCheck
armature for grounding by using test light or meterInspect armature insulation for indications of overheating or damaged windingsClean off any deposits of carbon or foreign matter which may contribute to later failure of the windings
rjl 4Check permanent magnetsMagnets should strongly attract any steel or iron object held inside the frame Weak magnets will cause excessive RPM on No Load Current Draw, Electric Starter test5Do not clean the starter drive assembly while the starter motor and drive are installed on the powerheadThe cleaning agent could drain into the starter motor, washing dirt from the drive into he starter bearings and commutatorAfter disassembling the drive, clean each part with grease solvent and inspect for wear or distortion6If the pinion does not properly engage the flywheel, the pinion and screw shaft assembly may be worn, distorted, or dirtyLocate the cause of binding and correct before completing assembly