Onan 4000 Microquiet quits after 20 minutes

[Natetheskate]

I have a Onan 4000 KY that will run for about 20 minutes, then starts surging and shuts down. It will start back up, then starts to surge again and shuts down after 10 minutes or so. The code reads "36", which is uncommanded shut down, and could be a number of things. I believe it is probably a fuel issue, but does anyone have any leads?

 

[WME]

Weird stupid stuff...Loosen the gas cap and see what happens

 

[DonTom]

I have a Onan 4000 KY that will run for about 20 minutes, then starts surging and shuts down. It will start back up, then starts to surge again and shuts down after 10 minutes or so. The code reads "36", which is uncommanded shut down, and could be a number of things. I believe it is probably a fuel issue, but does anyone have any leads?

See here.

-Don- Reno, NV

 

[udidwht]

First purchase a 'Kill O Watt' meter.

Plug it into an outlet (any) and start the generator and watch the voltage and Hz readings. Note what they are doing during run time.

Head over to smokestack forum and post up the issue...also get the service manual for your model (off label on front of generator)

Onan Generators

Restoring, operating, and maintaining vintage Onan generators. When asking questions about your generator, give your model number AND serial number. Smokstak Subscriptions, Support and Information

www.smokstak.com

 

[jubileee]

10 to one it’s vapor lock. I’ve moved the fuel pump and fuel lines out of the ” hot box” design on a dozen or more of those ky models.

You might try just moving the fuel filter and insulating all the fuel lines you can.

Rare instances of pin hole in fuel line contributing to vapor lock

 

[Natetheskate]

It was the pump. I changed out the fuel pump and the filter, all is well.

 

[DonTom]

I changed out the fuel pump and the filter, all is well.

It was probably just a clogged-up fuel filter.

-Don- Reno, NV

 

[Natetheskate]

No, and I can tell you why. After it quit, I went to prime on the on/off switch at the genset. The pump is supposed to run then, but it didn't.