Mercury 200 OptiMax Jet Drive Service Manual page 126

8. If the reading is above 15 volts at the battery without a battery isolator installed, the alternator is overcharging and must be
replaced.
a
Sensing Circuit
1. Unplug the red and purple excitation/sensing wire connector from the alternator.
2. Connect the positive (+) DMT lead to the red pin and the negative (–) DMT lead to the alternator ground.
3. The DMT should indicate the battery voltage. If battery voltage is not present, check the red lead for a loose or dirty connection,
or damaged wiring.
a
Excitation Circuit
1. Unplug the red and purple excitation/sensing wire connector from the alternator.
2. Connect the positive (+) DMT lead to the purple pin and the negative (–) DMT lead to the alternator ground.
90-8M0050731 MAY 2011
a - Alternator output stud
b - Alternator ground
b
32042
b
a - Sensing circuit red lead
b - Alternator ground
32044
Charging and Starting System
Page 2B-15