Suzuki outboard motors 1988 2003 repair manual., Page 152Get this manual
5-40 IGNITION AND ELECTRICAL SYSTEMS Do not apply full battery voltage to the field (brown) connectorAlways disconnect the battery ground cable before disconnecting the alternator leadAlways disconnect the battery (negative cable first) when charging itNever subject the alternator to excessive heat or dampnessIf you are steam cleaning the engine, cover the alternatorNever Use arc-welding equipment On the Car with the alternator connected, be checked directly or involve time-consuming test proceduresThis is the same method suggested for checking the capacitor discharge ignition boxOVERCHARGING There is really only one cause for this type of failure, the regulator is not working, t isn't controlling charging output to the battery, Since there is no repa of this part, replace iiUNDERCHARGING The charging system should be inspected if: Diagnostic Trouble Code (DTC) is set relating to the charging system The charging system warning light is illuminated The voltmeter on the instrument panel indicates improper charging (either high or low) voltage The battery is overcharged (electrolyte level is low andor boiling out) The battery is undercharged (insufficient power to crank the starter) The starting point for all charging system problems begins with the inspection of the battery, related wiring and the alternator drive belt (if equipped)The battery must be in good condition and fully charged before system testingIf Diagnostic Trouble Code (DTC) is set, diagnose and repair the cause of the trouble code firstIf equipped, the charging system warning light will illuminate if the charging voltage is either too high or too lowThe warning light should light when the key is turned to the ON position as bulb checkWhen voltage is produced due to the engine starting, the light should go outA good sign of voltage that is too high are lights that burn out andor burn very brightlyOver-charging can also cause damage to the battery and electronic circuitsto oav thorouahsystematic aoroach troubleshootina will, bia rewardsBuild your troubleshooting check list with the most likely offenders at the top Do not be tempted to throw parts at problem without systematically Troubleshootina the system firstDo visual check of the battery, wiring and fusesAre there any new additions to the wiring? An excellent clue might be, "Everything was working OK until added that live well pump With comment like this you would know where to check firstThe regulatorlrectifier assembly is the brains of the charging systemThe regulator controls current flow in the charging systemIf battery voltage is below about 14.6 volts the regulator sends the available current to the batteryIf the battery is fully charged (about 14.5 to 15 volts) the regulator diverts the currentlamps to ground, Do not expect the regulator to send current to fully charged batteryCheck the battery for possible draw with the key offThis draw may be the cumulative effect of several radio andlor clock memoriesIf these accessories are wired to the cranking battery then complaint of charging system failure may really be excessive drawDraw over about 25 milliamps should arouse your suspicionsThe fuel management gauge memory and speedometer clock draw about 10 milliamps eachRemember that milliamp is Vm of an ampCheck battery condition thoroughly because it is the #I culprit in charging system failuresDo not forget to check through the fusesIt can be embarrassing to overlook blown fuseYou must pull the battery voltage down below 12.5 volts to test charging system outputRunning the power trim and tilt will reduce the battery voltageA load bank or even pair of 12-volt sealed-beam headlamps hooked to the battery can also be used to reduce the battery voltageOnce the battery's good condition is verified and it has been reduced to below 12.5 volts you can test furtherInstall an ammeter to check actual amperage outputSeveral tool manufacturers produce shunt adapter that will attach to your multi-meter and allow you to read the amp outputVerify that the system is delivering sufficient amperageToo much amperage and battery that goes dry very quickly indicates that the rectifierlregulator should be replacedIf the system does not put out enough amperage, then test the lighting coilIsolate the coil and test for correct resistance and short to groundDuring these test procedures the regulatorlrectifier has not been bench checkedUsually it is advisable to avoid troubleshooting the regulatorlrectifier directlyThe procedures listed so far have focused on checking around the rectifierlregulatorIf you verify that all other systems stator are good then what is left in the system to cause the verified problem? The process of elimination has declared the rectifierlregulator badThis check around method is also useful on other components that can not If there is an undercharge condition after running the DC amperage check at the fuse assembly, then disconnect the stator coupling from the harness and perform AC voltage checks between the three stator leadsCheck between two stator leads at timeThere are three volt checks done to cover all possible combinations At idle, there is typically volts on each testIt can be higher if the idle is higherAll three readings should be equal, within volt or twoStator shorts to ground can be checked by doing voltage test between one stator lead and ground, engine runningThere should be roughly half the normal stator voltage check readingIf the readings are all within specification, the stator is working correctlyIf any or all readings are below normal, turn the engine OFF and check the stator windings using an ohmmeter An isolated continuity check and short to ground check should be doneIf the stator is bad, replace it since it can't be repaired The charging system is an integral part of the ignition systemFor information on service procedures, please refer to the "Ignition" section of this manualTESTING