1978 Johnson 55 HP Outboards Service Manual, Page 107Get this manual
CHARGING SYSTEM TROUBLE ISOLATION CHART PROBLEM: STEP Check battery state of charge and connecti onsBATTERY RUNS DOWN RESUL Battery Battery teryBattery battery holds chargeGo to step 2doesn't hoi chargeReplace batcable insulation wornReplace cabl es
PROCEDURE Add water as necessary and charge battery CI ean and tighten battery connectionsInspect cabl es for worn insulation
Check al ternator output
Clamp induction type ammeter on positive (red) battery cableRun engine in full throttle operating range See Figure 7-23Shut off engine, disconnect battery, check rectifier leads with ohmmeter set to high ohms seal eSee page 7-15 With key switch in "off" position and battery cab Ies disconnected at battery, test stator with an ohmmeter set to low ohms scal eSee page 7-14Connect an ammeter between the battery and the Iead to the accessory terminal stripTurn on all accessories and observe amperage draw