1973 Evinrude Norseman 40 HP Service Manual, Page 67Get this manual
BATT TESTS HY DROMETER TEST FLOA MUST BE FREE EYE LEVEL WITH LIQUID SURFACE MAKE CORRECTION FOR TEMPERATURE
LOAD TEST DISCHARG BATT RY RAT OF 20 MP ERES FOR 15 SE DS VOLTAG.E SHOULD OT DROP LOW 9a VOLTS (12 VOLT BAT)
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 electrolyte 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 80 F, subtract points from hydrometer readingFor each 10 above 80 F, add points to hydrometer readingAfter correcting follows: to 80 F, 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 FTerminal 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 seconds, 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 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 capacity