1988 Johnson/Evinrude "CC" 40 thru 55 Models Service Manual, Page 255Get this manual
3Capacity Test Satisfactory capacity tests can be made only when the battery electrolyte equals or exceeds 1.225 specific gravity at 80 (2JO C)4 Terminal Voltage Test
Use extreme caution during any load testing Improper procedures could overheat battery and cause electrolyte gassingThis might create an explosive atmosphereaVariable 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 testing Follow equipment manufacturer 's instructions regarding test period and meter readingscEngine Load for Resistance Disconnect charge coil connectors between armature plate and power packConnect voltmeter across the batteryCrank engine for 15 secondsIf voltage is 9.6 volts or higher at the end of 15 seconds, the battery has good output capacityU