1971 Johnson 60HP outboards Service Manual, Page 73Get this manual
7-3 All cell readings uniform and below 1.225 specific gravityRecharge to full charge and retestSee note3Variation of more than 30 pOints (.030) specific gravity between any two cellsBattery condition is que!tionableRecharge and retest before making replacementNote-Disconnect positive cable when charging batteryCCapacity Test Satisfactory capacity tests can be made only when the battery electrolyte equals or exceeds 1.225 specific gravity at 80 FTerminal Voltage Test 1VARIABLE LOAD lllGH 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 for 12-volt batteries at the end of 15 seconds, the battery has good output capacity2FIXED RESISTANCE TESTERThis equipment has built-in load for high-rate discharge testingFollow eqUipment manufacturer's instructions regarding test period and meter readings3ENGINE LOAD FOR RESISTANCEDisconnect and ground spark plug leadsConnect voltmeter across the batteryCrank engine for 15 secondsIf voltage is 9.6 volts or higher for 12-volt batteries at the end of 15 seconds, the battery has good output capacityBATTERY CHARGING Boost charge 12-volt batteries at 50 amperes for 20 minutes (1000 ampere minutes)If the charger will not give this rate, charge for an equal number of ampere minutes at best rate availableDO NOT boost battery more than this amount for the "light load test"If batteries are to be fully charged by means of quick charger, the FLOAT MUST BE FREE HYDROMETER TEST EY ON LEVEL WITH LIQUID SURFACE MAKE CORRECTION FOR TEMPERATURE