Chrysler 100, 115 and 140 HP Outboard Motors Service Manual, OB 3439, Page 78Get this manual
Test3C-O Unit (Bench Test)1Check battery voltage by connectingBATT P" test lead to positive battery terminal andBATT N" test lead to negative battery terminal Position voltage adjustment knob at extreme clockwise position Read voltage on voltmeter of testerVoltage must read 12 volts minimum 2Connect test leads from C-O tester as shown in Figure 12
CAUTION
WARNING
When battery test leads are connectedtheCD INtest lead from C-O tester isLIVE "Be certain it does not contact any metallic object or sparks may occur and possibly cause ignition of gasoline vapors