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Old 03-03-2018, 08:15 PM   #1
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Default Onan 2800 Microlite Runs great then randomly surges then dies...

My Onan 2800 Microlite is running erratically. It will idle fine for hours, and sometimes it will run great under a load, but sometimes it will randomly start surging and die {always under a load} for no apparent reason. There is no pattern to this. I wish there was. We are at 40 feet above sea level and it is hot and humid, and I am wondering about removing the "sea level" adjustment and adjusting it lower, or richer, as mentioned on some other posts. I have run Seafoam through the system directly at a 50/50 mix. I don't think it is the carb.

Any ideas ? Thanks, John
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Old 03-03-2018, 11:19 PM   #2
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.

Google for the red rover's onan trouble shooting guide.

it is a free download.
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Old 03-04-2018, 12:15 AM   #3
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Stay away from seafoam as it will create a huge pile of white smoke and muck things up.

Get some carb cleaner with the unit running spray some down the carb in various areas slowly as not to kill it while it is idling. Or if the unit is already warmed then spray some down the carb and wait a while to restart.

My onan 4000 with low hours would sometimes go into dipsh?? mode and idle up and down.

Treat this onan System like a carburetor vehicle of the past. After I spray the carb it purrs like a kitten.

If you got old oil in then its a good time to change it to remove all the gum resin out. But if oil is still newer then don't worry. Onans are tougher then they get credit for. Hope this helps.
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Old 03-04-2018, 01:17 AM   #4
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My bet is the fuel pump is about to fail. Just a guess. Replace it and all will be well. It (fuel pump)runs erratically when hot. I have failed three of them.
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Old 03-04-2018, 01:32 PM   #5
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Default Thank you for your responses !

I think I will try the non-Seafoam carb cleaner first since it is the simplest solution, but also realize that repairs like this are rarely that simple. I hope so.

If that doesn't work then the fuel pump is next. There is not a lot of room in my Onan Microlite 2800. I assume the fuel pump is in the back under the air cleaner from watching videos on replacing the fuel pump on other Onan's. I cannot find a video that is specific to the 2800 Microlite.

Can anyone offer any tips on replacing the fuel pump on a 2800 Microlite that is hanging under the back of my Roadtrek ? I can reach the access panel easily from underneath. (I have spent a lot of time down there already...), but I am wondering how to access the fuel pump and hoping it can be done without removing the generator.

Any insight will be appreciated. Thanks in advance, John
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Old 03-04-2018, 01:48 PM   #6
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I would second the possibility of the fuel pump being an the way out, but that is far from certainly the cause. It is likely not a plugged up carb as it runs OK for quite a while before the issues.

As to whether or not to use Seafoam, I would be afraid of it at all. It has been effectively used by dozens and dozens, probably hundreds of class B Onan owners over the years with great results. Spray cleaners and Seafoam are good for different issues. The spray works well when you have venturi and other orifice plugging in the airstream area, Seafoam is what will melt out the gelling in the tiny fuel passages within the carb wet areas. Personally, I have never heard of anyone saying that Seafoam messed things up.
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Old 03-04-2018, 01:57 PM   #7
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Try loosening your gas cap. worked for me.
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Old 03-04-2018, 02:17 PM   #8
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Default Thanks again for your responses ideas !

I found one site online that says the 2800 genset must be removed from the Roadtrek to replace the fuel pump and another site that states that there is an access panel under the genset that can be removed to access the fuel pump.

Can anyone confirm any of this info if it comes down the replacing the fuel pump ?
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Old 03-04-2018, 02:31 PM   #9
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I've replaced three Onan 2800 fuel pumps. There is no access panel and the unit must be removed from the Roadtrek. Have fun!

Airtex sells one cheaper than Cummins Onan.
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Old 03-04-2018, 02:37 PM   #10
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Okay. Thank you. The truth sometimes hurts ! I guess pulling the generator down is not that big of deal once you have done it once or twice. Is there anything I should know about lowering the genset ?
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