1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 350Get this manual
Charging System65 Tiller and Remote Electric Start, 100 Manual Tilt Models Description The charging system consists of the alternator, the rectifier diodes which change the alternating current output of the alternator to direct current, and the battery itselfThe alternator is made up of two partsthe flywheel with cast-in magnets, and the stator assembly which is secured to the crankcaseThe stator assembly is made up of coils wound over laminated iron coreAround this assembly the flywheel turns, inducing alternating current in the coilsThe rectifier assembly converts the alternating current to direct current
Troubleshooting the Alternator System65 Tiller and Remote Electric Start, 100 Manual Tilt Models
Failure in the charging system will usually show up when the battery becomes underchargedTo determine the cause of trouble, check first the condition of the battery and electrical connections throughout the circuitA visual inspection may be all that is required to locate the troubleCheck the following before proceeding with electrical testingDisconnect battery leads before tightening or changing connections on dash instruments or any part of the charging circuit1WiringCheck for corroded or loose connections, and clean and tighten all connectionsCheck for worn or frayed insulation2Check battery polarityCheck for damage to rectifier diodes as described under Rectifier Diode Test3Electrical loadExcessive electrical load from too many accessories will run the battery downIf visual inspection of the electrical system shows all components to be in good condition, an electrical inspection will be necessary to determine which component of the charging system is the cause of trouble