$600 carburator

First off, I have a 2014 Winnebago Trend I bought in Oct of 2014.

I was told today, that I needed to replace the carb on my Onan 2800 with 21 hours on it because it was tarnished and gunked up.  I looked at what he was talking about and it was a clean looking float bowl with a little black trash in the bottom. I told him to reinstall it, I would not be buying a new $600 carb.

I run this generator for 15 minutes on the first of every month.  It ran for hours just a few weeks ago. So 21 hours over 18 months is not a lot, but I have at least 5 hours on this gen just to keep it running!

I'll take the float bowl off and take a pix of what they call a tarnished carb. Then I'll throw it in the ultrasonic cleaner and see if I can bring it back to life.  If not, there will be a slightly used Onan 2800 for sale on EBay.  I don't think I'll be buying a MH with another Onan product on board.

Mike Freyder
2014 Trend 23B

15 minutes per month is probably doing more harm than good. The manufacturer recommends two hours under 50% load.

There is a YouTube video that covers how to re-build them.  I have watched it, but didn't bookmark it. They don't want you to know that you can, they just want to sell you a new one.  The guy that made the video ran into the same thing and said, no I am not spending that much money!

Happy Wanderer I don't see how, can you explain? 15 min is enough time to run the tarnish off the armature which is what the running is all about.  2 hours seems excessive and noisy to the neighbors. What I have is ethanol deposits I think, and that would be there if I ran it 20 hours a month.  I run it for three tenths on the meter with the air conditioning on which is approx 10 amps or half load for this 2800.

I do the same for a Coleman 3250 in the country for an elderly family member. Starts on the first pull every time. Onan should do no less for the price paid for it.

Do all of you experts run 2 hours a month if you have not used it for the prior month?  My 21 hours averages to approx. 1.2 hours a month run time. I'll drop this thing before I spend time holding it's hand. I have fun stuff to get done!

Mike
2014 Trend 23B

Not too many reports on the 2800 but this link to the 4000 is just about the same issue except his is cleaner from the pix. Mine does not have the solenoid on the bottom.

https://www.youtube.com/watch?v=Ph_C6XF2TCU

Pretty much what I am doing as we speak. It in the cleaner...

Mike

It may sound harsh, but your unit came with an owner's manual. You are doing exactly what the manual says not to, with the end result the same as described in said manual.

Just how is this the fault of the generator?

I was just wondering?
21 hours, nothing could be worn out.
Might,  running some gumout or some other cleaner solve a problem like this?

Not to argue, but you didn't answer the question?  My manual says 45 to 60 minutes. With a single two hour run better than several shorter runs.  Not to do a two hour run a month.  I'm doing that with my run on average 1.2 hours per month. So how is my once a month 15 minute run doing harm, you made the suggestion...

Your suggestion also was that I don't read the manuals.  I do.  I also observed many issues with the carbs just from a quick look at the Youtube videos, so how are those faults coming to be?  I guess all those people aren't reading the manuals either. 

Sorry you are harsh, and wrong in your advice. I'll stick to the manual.

Mike

Will it run? Runs rough and stalls? You never stated if it will run now or not? If it runs and runs rough get some Sea Foam and run it for an hour or two. It should clean the junk up. Does not to hurt to mix a little Marvel oil in the gas to keep things smooth.

Mfreyder said:

Not to argue, but you didn't answer the question

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I?ll let the manual answer your question:

It may seem surprising that ?not? using a machine could cause performance problems, but with RV generators that?s exactly the case. Regular ?exercise? is an important part of keeping your generator healthy. Lack of exercise can cause moisture build-up and fuel system degradation that make it run poorly. In fact, in as little as 30 days, the fuel in gasoline-powered generators can begin to gum and varnish the fuel system. Fuel varnishing results in hard starting and surging. (A surging generator never settles at a stable operating speed.)

To prevent such problems, it is recommended to run gasoline generators at a minimum of 50 percent capacity (2000-watts, or one air conditioner for a 4000-watt set) for two hours once every four weeks. This is necessary to help keep moving parts lubricated, expel moisture and control fuel varnishing in the carburetor. A long two-hour exercise period is preferable to several short periods. While traveling, this can be accomplished by running the air conditioning. If you own a diesel generator, regular exercising can help reduce internal condensation and helps keep seals lubricated.

Regular exercising the genset heats up the alternator windings and removes or expels excess moisture. In sets equipped with brushes, exercising helps prevent corrosion buildup on slip rings. Running the genset also brings fresh fuel to the carburetor on gasoline and diesel gensets.

Q. I will not be using/exercising my generator every month. What do I need to do?  A. Depending upon your location in the country, gasoline can start to deteriorate in as little as 30 days. Treat the entire fuel tank with gasoline stabilizer. Run genset for two hours at 50 to 70 percent load. This process will circulate the treated fuel through the entire fuel system.

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The last sentence implies that an extended run is required to assure that fuel sitting in the system is consumed.

Perhaps it?s just coincidence, but my generator is six years older than yours and has never had a problem. I follow the procedure listed above, including using fuel stabilizer when the motorhome sits during winter months.

It would almost start, but not come to an idle and kill. It pulls fuel from the MH fuel tank so adding anything to the fuel is out of the question.

Never sits during the winter, I use it all year, and go thru two tanks of gas a month. The bowl is not tarnished, no stale fuel. I'll still stick to my manual. Throw away carb on a $2000 gen, my Coleman has a kit listed for a $300 gen. Nothing else to say.

You can remove the air filter and spay some carb cleaner down the carb as you press the start button. Spray small amounts to keep the generator going. It might clean it and get it running again but be Careful as it could cause a backfire if you spray to much.  If you do get it running again 15 minutes is not enough and it should be run for at least a hour each month. I run mine for 15 minutes with light load and then I turn on the air conditioner for 45 minutes follow by turning off the air conditioner and letting it run for another 15 minutes with a light load before shuting it off. During the 1 1/2 hours I take the time to Inspect my RV and see if there is anything that need fixing. I also start the RV and run my engine and shift through the gears.

Disconnect the motorhome fuel line at the input to the generator's fuel pump and run a temporary line into a gas can with fresh fuel doped with Seafoam or another carb cleaner.

Start the generator and the fuel and cleaner will get sucked through the carburetor.

Restore the fuel line from the motorhome's tank and dump the remaining fuel/cleaner into the tank as good measure.

Mfreyder said:

The bowl is not tarnished, no stale fuel.

Click to expand...

The bowl is not the problem, it's the jets inside the carb. Do as suggested and connect a temporary gas can with a gas/SeaFoam mixture and run the generator under at least half load for an extended period. If that doesn't work, remove the carb and soak it in a can of cleaner such as Chem-Dip.

I remember a post on some website as follows:  If you get the Onan fuel pump number you can go on line and get a direct fit replacement "Airtex" replacement for usually less than $40.00.

Cheers

There is a jet on the bottom of the bowl. The fact that there is no tarnish in the bowl indicates it has not had stale fuel sitting in the bowl over months of non use. Happy to hear suggestions, but this thread was posted to let the buyer be aware that Onan charges $600 for a trash carburetor that can not be rebuilt.

Reread the original post, I ran this generator for 2 or more hours a couple weeks ago. With normal use I am running it over an hour a month. The exercise suggestion in the manual, is if the generator is not being used as in storage. Mine does not sit without use. My 15 minute run is in addition to check the gen when I am doing other checks. Onan would have done better to put a fuel shutoff valve so the fuel can be run out of the bowl.

The issue here is more ethanol damage, and the fact that if the carb needs to be replaced it cost $600 the price of a new gen at Home Depot. Nuts.

Kennedy Engine who I took it to for warranty work, says they are not allowed to "work" on the carb, they would rather sell $600 carbs.

Ever exercise a gen that does sit for a month with a fuel cut off valve? Takes about a minute to run fuel out of the bowl after cutting off the valve, not two hours. 15 minutes would ne more than enough to burn out fuel from the entire fuel line. This is an ethanol issue, I could run it for 20 hours and still have ethanol fuel in my carb.

I have three generators, a riding mower and have never had a problem with my maintenance procedures until this Onan.

I'll remove the carb and run it in the ultrasonic cleaner. The hope was that the fuel was not getting past the jet in the bottom of the bowl, and cleaning it would get it running. That did not work, I'll drop the entire carb in and see what that does.

Thanks whiteva, that is helpful info! If cleaning the entire carb does not do it, I'll look into it.

Yes, you can clean or rebuild the carb. It is time consuming, though, and at Onan shop labor rates a new carb is probably about the same price and the shop doesn't risk having the cleaning job fail to fix the problem.  Your time is cheaper, so cleaning makes sense as a DIY project. Seafoam or similar may do the job, or may not, but I would certainly try it. Next step would be replacing the jet(s), assuming they are available by themselves.

Onan used to recommend 30 minutes/month "exercise", but now has upped it to two hours. I agree that is unreasonable for a consumer-level product, but that is their current recommendation.  The exercise does two things, and I'm not sure which one led to the 2-hour exercising. Carb cleaning is one need, but the other is driving out moisture from the stator & armature with the engine heat. Moisture is a leading cause of generator (as opposed to engine) malfunction.

That carb is showing moisture deposits. There is a brass jet in the bottom that needs to be cleaned up. I would install a line valve on it and run it dry before storage.

I have never had a Onan cab apart but all small engine carbs look about the same. Clean the bowl and then look at the stem hanging down and you will see a little brass fitting, remove if and clean the hole of any varnish. If your unit has a manual pump switch run it to make sure gas flows through the needle and seat, if it does gently push up on the bowl to make sure it shuts off. Put it back together and start it.

Denny