Joe

[Joe]

I have an Onan 2800 gasoline generator. Ran fine all winter for maintenance runs. Ran for hour with load on lime normal. One day generator starts hunting and shuts down. Then woukd not restart for long time. Seems to run for 10 to 15 min. then hunts and off it goes. Oil level good and changed. Used carb.cleaner but still cuts out. It seems to be getting hot and shutting down until cools off. Not sure about hot but does seem to be hotter than used to be. Any ideas out there???

[EnduroRdr]

Maybe it’s running out of gas.
You may have a partially plugged fuel filter, and the carb bowl may be running dry after 10-15 min.

Just a guess but sounds like running out of gas.

[Knit]

Is it showing any error codes? Onan controls have flashing lights that can help figure out the problem. Here’s a page from KV series. Once you have code do a search like “onan error code 35” to see what it is.

[Deano]

Same symptoms as mine when the fuel pump was going bad.
Open the inspection plate and "T" connect a fuel pressure gauge in the fuel line. Should show approximately 4 PSI when running. When cool, the pumps seem to work and then lose pressure as they warm up.

As the pump was being replaced, I relocated the new pump outside of the generator housing, both to facilitate a future replacement, as well as moving it to a cooler location.

[jbucking]

When they begin to fail the Onan fuel pump will pump fine while cool, and then fail once it warms up. Once at operating temp the generator will hunt and then starve for fuel. It has something to do with the contacts in the fuel pump separating when worn after attaining operating temperature. My 2800 did the same thing and replacing the fuel pump was the fix. You can unhook the fuel line running to the fuel filter and see if it pumps fuel once the motor is hot and stops running. It should pump fuel when you press the remote start button on the generator. If it does not pump fuel. (Please catch the fuel and don't set yourself on fire under there....) then it is likely the pump.

Unfortunately, replacing the fuel pump (on most class B's) requires removing the generator from the chassis to access the pump. It's a $40.00 part with $500.00 worth of labor unless you want to tackle that one yourself.

[blackbourn3704]

Another way to check the fuel pump is to disconnect the fuel line at the carburettor and plug it. Then set up a gravity feed from a gas can to the carb using a siphon hose. the gas can has to be higher than the carb of course.

[JohnnyFry]

It seems like it would be relatively simple to install a new fuel pump outside the case and leave the old one in place. The only problem I see is getting the power wire out of the housing. Any thoughts? Can one cut a hole in the case with a hole saw and fish the wire out?

[blackbourn3704]

Removal of the generator is not all that hard if you have access to a portable engine hoist. You can work some straps around the genset fairly easily, then hoist away. I am trying to attach a picture. Hope it works!

[Joe]

Wow thanks for all the suggestions. Going to check out for fuel pump issues and let everyone know.

[Joe]

Ran gen today for about 20 min. Then it died, no hunting just died. Pulled fuel filter off and blew thru it. Gas came out no restriction. Hit start switch and gen started. Noticed gas not pumping at steady rate. Going to try gravity feeding fuel to check pump.

[blackbourn3704]

Here is another forum that I found very helpful.
https://www.smokstak.com/forum/forumdisplay.php?f=1

Good luck,
Bob

[Deano]

Originally Posted by blackbourn3704

Removal of the generator is not all that hard if you have access to a portable engine hoist. You can work some straps around the genset fairly easily, then hoist away. I am trying to attach a picture. Hope it works!

On my RT 210 the generator is mounted under the body. It has to come out from under.

[Deano]

Originally Posted by JohnnyFry

It seems like it would be relatively simple to install a new fuel pump outside the case and leave the old one in place. The only problem I see is getting the power wire out of the housing. Any thoughts? Can one cut a hole in the case with a hole saw and fish the wire out?

Had I known exactly were the fuel pump and feed wire were located I could have used a hole saw to access the wire.
IIRC, a 1" hole, or larger in the drivers side, front corner of the generator housing would have allowed me to fish the pump wire out enough to connect an external pump. Essentially doing what I did without having to drop the Generator and opening the housing.
I would suggest routing a new hose from the external pump through a new hole at the rear of the housing to the carburetor in lieu of leaving the old pump in the circuit.