you should have around 13 to 15 volts when running on the battery terminal. Sounds like the alternator is not working. Check the CB between the alternator output terminal and the battery terminal.If you can afford another $70 or so, get a mercury service manual, it has some pretty good trouble shooting and checkout procedures for the electrical system. Make sure the field is being energized when the ignition switch is on.Here is a link to a fair description of how the charging system works.good luckjwthttp://www.google.com/imgres?imgurl=htt … CBwQ9QEwAQ