Chrysler 75 and 85 HP Outboards Service Manual OB 3646, Page 74Get this manual
3If battery and cranking voltage are all rightproceed as follows :
AConnect test leads from C-O tester as shown in Figure 10
BAdjust battery voltage to 12 volts on voltmeter by turning voltage adjustment knob counterclock wiseTurn indicator knob to full clockwise position so that mark on knob is at100" setting
CAUTION
When making connections of test leadsthe "C-O IN" lead isLIVE" when battery leads of tester are connectedConnect battery leads as final connections