1992 Johnson Evinrude "EN" 9.9 thru 30 Service Manual, P/N 508142, Page 290Get this manual
3Capacity Test Satisfactory capacity tests can be made only when the battery electrolyte equals or exceeds 1.225 specific gravity at 80 (2]0 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)