Onan HDKAJ Diesel generator shutdown - Error 25

[cotten31]

I have replaced the fuel filter. I have done the fuel flow test and it passed.
Here is my last experience starting the generator

1st start - ran at high idle (no surging) until 1:12 and then killed.

2nd start - ran at high idle and surging until :45 seconds. lower idle at 1:08. killed at 2:10

3rd start - ran at high idle with surging. lower idle at 1:06 & surging stopped when dropped to lower idle. At 1:58 it dropped to an even lower idle. killed at 2:15

4th start - ran at high idle with surging. lower idle at 1:00 & surging stopped at 1:15. At 1:50 it dropped to an even lower idle. killed at 5:20

5th start - ran at high idle with surging. lower idle at 1:00 & surge ended at 1:04. At 1:59 it dropped to an even lower idle. It ran for over 24 minutes then I shut it off.

There was never any load put on during any of this. And always error 25.

Now if I put a load on it as soon as I see it generating electricity, it doesn't shutdown. So if I put a load on it right off the bat, it will run. And it will continue to run after the initial load is removed.

This is in a'98 Monaco. Thanks for any advice. Jeff

[cotten31]

Update:
The problem is worse when it is colder outside. Saturday morning it killed sooner and more often. But I kept starting it up and it would run longer each time until finally it kept running. Putting a load on it asap definitely helps it stay running at start up. Once it warms up, I can remove the load and all is fine.

[WILDEBILL308]

It may be air in the fuel system. See if you can keep starting it and you may purge all the air from the system.
Bill

[Passin_Thru]

Remove the filter again and put it back on. Remove the return line and see that you have a fuel flow. Sounds like you are getting air, causing a surge and overspeed indication. Could be a cracked line or a loose fitting fitting. It is real easy to screw up those filters the way they are made. Obvious reason is it has enough fuel to run 5 min so you et full flow but maybe the filter is emptying out due to leak before it. Check the oil and make sure you have it full of coolant. Sometimes computers lie. They are taking over the world as you can see. Keep it simple. Just trace it back.

[cotten31]

Thanks - I know what the service manual indicates. I'm trying to get advice on how to fix it without going to a shop.

[bshpilot]

FAULT—CODE NO. 25

ENGINE ABOVE SPEED TARGET - (Governor unable to regulate to target speed)
Corrective Action: See an authorized Onan dealer.

[okgc]

ENGINE ABOVE SPEED TARGET FAULT—CODE NO. 25
(Governor unable to regulate to target speed)

Corrective Action:
See an authorized Onan dealer

Onan HDKAH, HDKAJ, HDKAK, HDKAT, HDKAU, HDKAV Operator manual