1974 Johnson 40 HP Outboard Motors Service manual, Page 74Get this manual
BATT ER STS HYDROM TER TEST FLOAT MUS REE YE ON VE WI TH LIQUID SURFACE MAKE CO RRECTION OR TEM RA URE
0 LOAD TEST DISCHARGE BATTERY AT RATE OF ZOO ,AMP ES 15 SECONDS VO LTAG SHOULD NOT DR OP BELOW VOLTS (IZ VO BA T
Figure 7-3Testing Battery The sources of deficiencies noted in the visual inspection should be located and corrected before installation of new batteryBHydrometer This test can only be used when there Is sufficient el ectrolyte above the battery plates to fill the hydrometer tubeDo not, however, take readings immediately after refilling the cells with waterSpecific gravity will vary points (.004) with every 10 temperature changeFor each 10 below 80F, subtract points from hydromete readingFor each lO above 80F, add points to hydrometer readingArter correcting follows: to 80F, interpret readings as CCapacity Test Satisfactory capacity tests can be made only when the battery electrolyte equals or exceeds 1.225 specific gravity at 80 Terminal Voltage Test 1Variable 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 for 12-volt batteries at the end of 15 econds, the battery has good output capacity2Fixed Resistance Tester This equipment has built-in load for high-rate discharge testingFollow equipment manufacturer's instructions regarding test period and meter readings3Engine Load For Resistance Disconnect and ground spark plug leadsConnect voltmeter ac ross the batteryCrank engine for IS secondsIf voltage is 9.6 volts or higher for 12-volt batteries at the end of 15 seconds, the battery has good output capacity