Onan Gen Set

[Wilkiesr]

Onan Emerald Plus 5000 Gen-set won't run. Starts runs erratic and surges. This just started all of a sudden.I have blown out fuel line, took carb. apart it was clean.Fuel filter is not clogged. Air filter ok. where is the low oil safety switch i have not checked that. I am going to install new fuel pump,fuel filter,air filter,plugs plug wires.etc. This unit only has 477 hrs.

[hivoltage98]

Your due for a full preventive maintenance on the genset. You should also change the brushes and clean the rings. You'll have to disassemble the genset and remove the flywheel to access them. That's probably why your getting erratic voltages.
If you don't change the brushes the genset will eventually shut down on fault.

[CJ7365]

Originally Posted by hivoltage98

Your due for a full preventive maintenance on the genset. You should also change the brushes and clean the rings. You'll have to disassemble the genset and remove the flywheel to access them. That's probably why your getting erratic voltages.
If you don't change the brushes the genset will eventually shut down on fault.

I have to disagree about changing the brushes, that unit only has 500 hrs on it. I know of no one, except maybe you that changes the brushes as preventive maintenance. Cleaning the rings only necessary if the gen set hasn't run in a long time.


If the rings are corroded, the genset will not even run.

No where does the OP mention anything about erratic voltages

Surging and erratic running is a system of fuel problem, carb varnished up etc....

I think your going the right way OP with what you are doing, plugs, fuel filter etc.


Do you have any codes present??

[hivoltage98]

Well I'm glad you have your opinion but I also have mine. My ky genset has 477 hours and the brushes were shot. That produced carbon from not having good contact on the rings, thus it went out on fault. But before it went out on fault it was being erratic.
Hours on a genset are good to go by but the load also dictates brush and genset life.

[marjoa]

Here's some links that may prove helpful:
http://www.irv2.com/forums/f59/just-...rs-101868.html

http://www.irv2.com/forums/f54/onan-...wn-178629.html

http://www.irv2.com/forums/f258/gene...ue-102852.html

[hivoltage98]

Originally Posted by marjoa

Here's some links that may prove helpful:
http://www.irv2.com/forums/f59/just-...rs-101868.html

http://www.irv2.com/forums/f54/onan-...wn-178629.html

http://www.irv2.com/forums/f258/gene...ue-102852.html

Great article on the slip rings. I'm in the process of preventive maintenance and also repair of the worn out brushes.