1998 Johnson Evinrude "EC" 90, 115 SPL Service Manual, P/N 520209, Page 245Get this manual
Cranking Discharge Method
1Check battery voltage If voltage is greater than 12.5 volts, go to Step If voltage is less than 12.5 volts, go to Step 32Separate the ignition charge coil connector(s}Crank engine in short bursts until battery voltage is less than 12.5 voltsCheck battery voltage with key in the OFF positionINotel Disconnect engine battery cables before proceeding with this check
3Connect 0-40 amp ammeter in series between the rectifier regulator red lead and the battery side of the starter solenoid 4Reconnect the engine's battery cables Reconnect the ignition charge coil connector(s}