Onan 7500 Diesel gen problem

[LVRVLUVR]

Originally Posted by MikeandJan

I wanted to followup with everyone who tried to help with my generator problem. The generator was throwing a 31 code - engine overspeed - and the corrective action is to see an authorized Onan dealer. I took it to Register RV in Brooksville, FL, where I already had an appointment to have StoneVos slide toppers installed. In addition to the 31 code, their tech also got a 28 code one time. The corrective action for both is to replace the controller/inverter on the generator - $1,850 for the part and about 4 hours labor. When the tech removed all the covers on the way to the controller, a large part of a magnet was laying there stuck to the frame and small bits of magnet were all over. The cooling fan, rotor, and stator were all damaged and had to be replaced. No one had any idea why the magnet came loose - they are "bonded", i.e., glued in place. Total cost parts and labor came to $3,000. The good news is that the controller/inverter was good and we didn't have to install a new one.

The folks at Register were super and the tech took a lot of time explaining the system to me. The controller senses the generator load requirement and adjusts the power output of the engine by adjusting fuel flow. In my case the generator couldn't produce power so the controller would ask for speed up to the max of 2100 RPM at which time it would shut down the engine. After the repair, they ran it for 5 hours with no problem I also ran it 10 hours all the way back to North Carolina and it performed just fine. Thanks again for your ideas.

is that a just happened or could it be something from the shop that changed the oil...
I have the same gen and was going to have a shop. Cummins service it

maybe better just do it my self

sorry to hear this about your gen,... seems to me that that shouldn't have happened.... did you remove the soot plug? most the time they won't do it unless you ask...

[bruceisla]

Originally Posted by LVRVLUVR

is that a just happened or could it be something from the shop that changed the oil...
I have the same gen and was going to have a shop. Cummins service it

maybe better just do it my self

sorry to hear this about your gen,... seems to me that that shouldn't have happened.... did you remove the soot plug? most the time they won't do it unless you ask...

It's highly unlikely the failure was caused by the shop work.

from an old post on a different forum:

"Well, I see this issue has been cussed and discussed on this forum before. I was told that it's not uncommon for the adhesive that Onan used to attach the magnets to the rotor to fail, leading to catastrophic failure of the genset. Isn't this something? Only 360 hours of use and this is all the better you get. Unbelievable! Well, like I said, thank God for the warranty, and thank God it happened before the warranty was up. I was also told that Onan has changed the design now and aren't using adhesive any longer".

[LVRVLUVR]

Originally Posted by bruceisla

It's highly unlikely the failure was caused by the shop work.

from an old post on a different forum:

"Well, I see this issue has been cussed and discussed on this forum before. I was told that it's not uncommon for the adhesive that Onan used to attach the magnets to the rotor to fail, leading to catastrophic failure of the genset. Isn't this something? Only 360 hours of use and this is all the better you get. Unbelievable! Well, like I said, thank God for the warranty, and thank God it happened before the warranty was up. I was also told that Onan has changed the design now and aren't using adhesive any longer".

wonder what year they changed, and if there is an up grade to do to stop it from happening

[jondrew55]

Sounds like there is a $3000 upgrade

Originally Posted by LVRVLUVR

wonder what year they changed, and if there is an up grade to do to stop it from happening

[outofcontrol]

I have a 2004 American Eagle with a Onan 7500 Quit Diesel. I heard a loud noise and ran outside to turn it off. I took cover off top of generator and found pieces of magnets everywhere. I am assuming this is part of the stator or armature. Not sure what to do. Was thinking of taking the sections out in hopes to find a complete section to replace it myself. Any thoughts?

[outofcontrol]

I noticed a few days prior to this that the generator would dye and seemed like it was struggling to just carry the load for both air conditioners.

[outofcontrol]

Has there been a recall on these generator and was wondering if it was covered under this recall

[sewerdog]

THanks for info.