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Joshj · 05-05-2021, 07:04 PM

I have a Onan 4000. I’ve changed the fuel pump, fuel filter and spark plug, took the carburetor apart and clean it well, it still shuts off under load ( a/c and water pump can’t run at the same time) the air will stay on for bout and hour and the gen will shut off any suggestions?

txcpl · 05-06-2021, 04:57 AM

Go to the Onan site and pull up the booklet for your generator model. In it will be a page that explains the blinking light codes which occur on the starter switch. The code will tell you where to start looking for answers to your problem.

whybother · 05-06-2021, 07:04 AM

Quote:

Originally Posted by Joshj

I have a Onan 4000

Which Onan 4000 and spec? (For example, Model 4KYFA26100B is a 4 KY, Spec B.)

Different spec 4K's will have different troubleshooting procedures.

Joshj · 05-06-2021, 02:53 PM

The model number is 4bgefa26101n

Joshj · 05-06-2021, 02:55 PM

This one does not have the light on the start button

whybother · 05-06-2021, 03:32 PM

Quote:

Originally Posted by Joshj

The model number is 4bgefa26101n

I think this is the service manual for it:
https://onan.xmsi.net/965-0528%20Ona...0(09-1994).pdf
And:
https://onan.xmsi.net/965-0528%20Ona...0(11-1995).pdf

I'm not too familiar with the 4BGE, but when it's running, does it seem like it's running rough? Bad fuel mixture?

Joshj · 05-06-2021, 05:41 PM

It seems to be running pretty smooth when it’s running.

Joshj · 05-06-2021, 05:46 PM

I’m curious if it has something to do with the governor rod, it seems to be a little stiff to me, idk how stiff it supposed to be or if that has anything to do with it when I put a load on it

whybother · 05-07-2021, 09:02 AM

Quote:

Originally Posted by Joshj

a/c and water pump can’t run at the same time

Isn't the water pump DC? It seems strange that a DC item would be the thing to push it over the edge.

But, if the genset gets to a low AC voltage or frequency condition, I'm pretty sure it'll shut off -- and weak spark, running too lean/rich, etc., could cause the engine to not have enough power to keep up with demand, so double check your air filter, ignition coil, plug wires, fuel mixture, spark plug gap, ignition timing, make sure the choke isn't sticking, etc. Oher things to check would be oil pressure switch, oil filter, oil level, etc.

Check the AC voltage and frequency while running various AC appliances. Does the engine sound like it's struggling with higher AC load? Does the AC voltage and/or frequency go out of whack?

Does it start right back up after shutting off?

twinboat · 05-07-2021, 09:55 AM

If it was the governor or any rods and linkage to it, it wouldn't run an hour and then die out.

How did you clean the carb ? Did you find the main jet ( brass thing with tiny hole in it, up the main passage ) and clean that ?

I take a 14 gauge stranded wire, strip two inchs of insulation off it and use it like a tiny brush, up thru the jet.

Joshj · 05-07-2021, 01:07 PM

Yea, it will start right back up after shutting off, and it will still run the AC after starting back up,

Joshj · 05-07-2021, 01:08 PM

That’s how I cleaned the main jet and then blew some carb cleaner through it

tap4154 · 05-07-2021, 02:32 PM

Some people have reported that the dipstick is not correct on the Onan 4000. If you have oil up to the full line, I've seen folks say it will overheat the oil and cause it to shut down. The solution I've seen is to just fill it to about a quarter inch above the add line. I keep mine right in between the add in full line, and it doesn't shut down.

Joshj · 05-08-2021, 12:35 PM

Thanks for all the help, input and info. My brother works on generators in the military and I had him look at it, he said the governor was sticking and not letting enough fuel in, he took the carb and governor off clean them real good and the governor rod had been rubbing something. Put it all together and everything works just fine now