Onan Woes

[luvrbus]

OK it is a Emerald 4000 it starts fine but when you release the stater it dies, the ? is how do you check the voltage regulator and the board to see which is bad the brushes and the rings seem to be fine I don't have a manual and with my mobile internet service it would take a week

[Lin]

Clifford, here is a link to a forum where this exact problem is discussed.  While several of the posts are obviously way off, some others are good.

http://www.rvforum.net/SMF_forum/index.php?topic=48719.0

This one seems okay:

"The symptoms you describe (runs until you take your finger off the start button) are generally indicative of one (or more) of four things. They are, dirty or oxidized slip rings from non use, a bad voltage regulator, a bad circuit board, or a defective oil pressure switch. I would start by cleaning the slip rings...."

He also provides a link to a trouble shooting guide.

Aside from that, they say that the unit will shut down if it is not producing 120v.

[wg4t50]

The simple test is to read the ac voltage while holding the start button, if it is over 95 volts ac, the issue is the control circuit board.
If the voltage is below about 70 volts, it would be the regulator.
All assuming it is running near 1800 rpm / 60 hertz
OR a loose / broken wire anywhere.

If you give me the complete model, spec & serial number, I will email the service manual, might help check it out.
Dave M