1993 Johnson Evinrude "ET" 40 thru 55 Service Manual, P/N 508283, Page 275Get this manual
3Capacity Test Satisfactory capacity tests can be made only when the battery electrolyte equals or exceeds 1.225 specific gravity at 80 (2r C)4Terminal Voltage Test
ill procedures
Use extreme caution during any load testingImproper could overheat battery and cause electrolyte gassingThis might cause an explosive atmosphereaVariable Load High Rate Discharge Tester (Recommended)