1992 Johnson/Evinrude EN 2.3 thru 8 outboards Service Manual, Page 256Get this manual
After correcting to 80 (27 C)' interpret readings as follows: All cell readings uniform and above 1.225 specific gravity indicates battery is serviceable, but may require charging All cell readings uniform and below 1.225 specific gravity, charge fully and retest Variation of more than 30 points (0.030) specific gravity between any two cells, indicates battery condition is questionableRecharge and retest before replacing battery3Capacity Test Satisfactory capacity tests can be made only when the battery electrolyte equals or exceeds 1.225 specific gravity at 800 (27 0 12009
C)4Terminal Voltage Test Use extreme caution during any load testingImproper ill procedures could overheat battery and cause electrolyte gassingThis might cause 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 testingFollow equipment manufacturer's instructions regarding test period and meter readingscEngine Load for Resistance Twist and remove the spark plug leadsConnect 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 capacity