1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 355Get this manual
Checking the RectifierRegulator Assembly Charging System100 Power TrimTilt Models and 155 Models Description The charging system consists of the flywheel, alternator, recti fierregulator assembly and the batteryBuilt into the rectifier regu lator assembly is the rectifier that changes alternating current into direct current and the regulator which controls the battery voltageChecking the RectifierRegulator Assembly The following conditions could result when the rectifierregulator assembly does not function adequatelyno output resulting in an undercharged battery, low output resulting in low or undercharged battery, or too much output resulting in an overcharged batteryThe following method of loading the battery to lower the battery voltage should only be used if no other load is available (such as automotive head lamps)1Check the battery voltage with voltmeterIf battery voltage is under 12.5 volts, go to step 3If voltage is higher than 12.5 volts, go to step 22Separate the two charge coil connectors (2-wire)Crank the engine until battery voltage is between 12 and 12 12 voltsCheck voltage with the key in the "Off" positionCrank the engine in short burstsDamage to the starter motor may occur if overheated3Disconnect the battery cables at the batteryConnect an ammeter between the red lead of the rectifierregulator assembly, and the battery terminal of the starter solenoidUse an ammeter that will indicate 10 amps for 10 amp charging system, 35 amps for the 35 amp charging systemReconnect the battery cables at the battery4Reconnect the charge coil connectorsStart and run the engine to 4500 rpm (10 amp charging systems), 4000 rpm on 35 amp charging systemsAmmeter shou Id indicate full output5 Continue to run the engine at the above rpmThe voltmeter will begin to show higher battery voltage readingAs the voltmeter approaches 14 volts, the ammeter will show decrease in currentAs the current decreases, the voltage across the battery should stabilize (regulate) at 14 to 15 volts12 16 8