1993 Johnson Evinrude "ET" 60 degrees LV Service Manual, P/N 508286, Page 229Get this manual
3Capacity Test Satisfactory capacity tests can be made only when the battery electrolyte equals or exceeds 1.225 specific gravity at 80F (27C) [3] 4Terminal Voltage Test
ill procedures
Use extreme caution during any load testingImproper could overheat battery and cause electrolyte gassingYou might create an explosive atmosphere
aVariable Load High Rate Discharge Tester (Recommended) Connect tester to battery terminal postsDischarge at rate of three times battery ampere hour rating for 15 secondsIf the voltage is 9.6 volts or higher at the end of 15 seconds, the battery has good output capacitybFixed Resistance Tester This equipment has built-in load for high-rate discharge testingFollow equipment manufacturer's instructions regarding test period and meter readingscEngine Load for Resistance Twist the spark plug leads and remove them from the spark plugsConnect voltmeter across the batteryCrank the engine for 15 secondsIf voltage is 9.6 volts or higher at the end of 15 seconds, the battery has good output capacity