1993 Johnson Evinrude "ET" 40 thru 55 Service Manual, P/N 508283, Page 295Get this manual
RectifierRegulator Tests12 Amp Models Variable Load Tests To test the operation of the rectifierregulator, you must be able to run the engine continuously at approximately 4500 RPM, either in test tank, on marine dynamometer, or on the boatThe test consists of monitoring the system's response to partially discharged batteryTwo methods for performing this test are described belowVariable Load High Rate Discharge Tester The rectifierregulator requires battery voltage on the purpie lead to operateBefore proceeding, verify battery voltage at terminal strip purple leads when key is ON1Disconnect battery cables
L1 rectifierregulator red lead and the battery side of the starter
solenoid
2Connect to 40 amp ammeter in series between the
L1 ble load tester (carbon pile) across the battery terminalsSteven's Instrument Model NoLB-85 and Snap-on Model NoMT540D are examples of testers available