Onan Marquis Gold 7000

[voltdr]

It shut down again. This time it is a code 41.
GENERATOR ROTOR FAULT—CODE NO. 41
(Controller unable to sense field or output voltage)
Restarted and ran for about 15 seconds and gave the code 36 again.
Is that a controller issue or generator issue?
Dan

[voltdr]

Thanks for the info Rich. I will try the fuel line crimp and see how it shuts down. I agree about the deflector. This genset has run for 2000 hrs without one, why would that be a problem now. Might have to bite the "controller" bullet. Where is the controller located? Is it behind the stop/start panel?
Dan

[voltdr]

Rich,
After crimping the fuel line and observing how it shuts down, it's definitely different than how it has been shutting down. It shuts down abruptly when running normally. I will order a new controller. Mine is the HGJAB model. Is the controller the 300-5047 or 300-5374?
Thanks again.
Dan

[Rich Biebel]

The ECU is mounted behind the start/stop switch in a second section.

You have to remove the battery cable....remove that front switch box section. 1 10mm bolt to remove it.

3 10mm bolts hold the rear box with ECU inside.
2 bolts forward.....1 bolt in the rear....behind the box and down...
1 connector with a snap lock disconnects the ECU from the wiring harness......Pull it and examine the pins carefully for any that look discolored.....might be your problem but probably not...

ECU is held in that rear box with 2 screws......slide right out....
Heat sink on one side gets some air from the machine when it runs...


2000 hrs......is well more than enough to have this problem.....

Make sure the brushes are good if you did not check them....they also fail and cause odd shutdown faults.....easy to check...

Look at the upper area of the generator end....behind the switch area.....
2 wires going into a holder....one 10mm bolt......
Brushes are there....remove bolt....slide brush rig out.....brushes are about an inch long when new.....If one is bad it will cause the surface it rises on to be in bad shape.....sandpaper on a wooden stick will clean it up if needed.....they car copper slip rings....
Brushes are easy to get.....#212-1303 and probably also available from Parts for Techs...

[voltdr]

Rich,
Thanks for the advice. I removed the Controller and checked the brushes. They looked good but are only about 1/3" long. I ordered a new brush block and brushes. I'll post again after I change the parts and run the generator.
Dan

[voltdr]

Update.
I installed the new ECU and brushes. Generator has been running now for over 4.5 hours w/o shutting down.
FYI. I purchased the ECU from a company called Flight Systems in PA. It has a 2-year warranty. $329
Thanks again for your help Rich.
Dan

[Rich Biebel]

Glad to help.

We have sent many PC boards to Flight for testing and repairs.
We also have used some of their replacement components for Onans like voltage regulators.
The control sold by ASAP is probably a Flight....

[voltdr]

Found my answer

[voltdr]

Rich,
I noticed that my air compressor in my trailer was starting slowly. I checked and generator was only putting out 91VAC.
I reinstalled the old controller and the generator output was back to 119VAC.
I sent the new unit back to Flight Systems. They told me that the new controller (300-9374) was checking good. I think they are having trouble with their unit since my old controller makes the generator output normal.
They were going to recheck their controller.
I'll let you know what they say.
Dan

[Rich Biebel]

They are guaranteed I believe so ask for a replacement.

I have had some that were not right from them.

Electronics !!!