Onan Carburetor Blues! $$$$$$$$$$$$

DesertRatt · 09-02-2020, 07:45 AM

My 2004 E/450 Minnie Winnie has the infamous "Onan Carb Clog". DANG!

First problem: Getting a new one is near impossible. I've been waiting weeks for a back ordered one to arrive at my fixit shop.

Second problem: He want's the astronomical sum of $992.00 for the carb and installation!

So, after doing the usual online snooping, I find out a few things. Ebay has replacements for $35, but apparently, they are junk and not worthy of the task compared to the $395 OEM Cummins part. Sumpin' is fishy in Denmark!

I've watched sever Utubes about cleaning stuck carbs, with SeaFoam(?) etc, etc.(see:

https://www.youtube.com/watch?v=wX6Pbh7HEMU

)
I've watched Utubes about replacing them with the new OEM carb.

So, now I'm thinking....maybe this IS a DIY project after all, and I can avoid this monster repair bill.

Anyone with direct experience on these things? My inclination is to pull the whole thing out and rebuild the entire generator to new condition, or alternately, replace it without something more reliable.

Thoughts?

Bones2003 · 09-02-2020, 09:12 AM

For what its worth, here is my experience. My generator starting having surging problems so I did the recommended routine maintenance which it needed anyway. If you are a DIY type person, this isn't too hard and not too expensive. I changed the spark plug, air filter, oil, fuel filter, and the rubber fuel line from the main tank. I felt better after doing it but it didn't solve my surging issue. The only two items left were the fuel pump and the carburetor. Since the SeaFoam process is also fairly easy and inexpensive, I tried it and it solved my surging problem. In my case, I guess the carburetor was not "clogged" or broken - it was just kind of gummed up. It's been working great for the past year now.

If you do change the oil, read up on the forums about the correct fluid level to re-fill it. Too little is bad, too much is bad, and on some units you cannot trust the level indicator in the oil fill cap to show you the correct level.

DavidM · 09-02-2020, 11:32 AM

I have fixed maybe a dozen lawnmower and outboard motors by removing the carb, partially disassembling (rally just separate the float bowl from the body) and soaking it in a can of carburetor cleaner overnight.

95% of carb problems are due to today's gasohol which forms a sludge if it is not used regularly. Soaking dissolves it. Carb cleaner can be bought at any auto parts store.

David

hank857 · 09-02-2020, 11:49 AM

there is a product called mechanic in a bottle. I have used it on portable generator and it works. you would need to fix up a separate fuel supply to run it initially. I found it at home depot in lawn section and it is available on the net, probably at ace etc. Once you get everything running make sure to run stabil into the system for storage. When i refuel for last time I put the stabil in and then run the generator while driving to ensure it gets into the gens fuel system since it does not draw a lot when running.

DesertRatt · 09-02-2020, 12:59 PM

Thanks for the tips guys. Not sure if I want to even keep this model Gen. I'm very unimpressed with the millions of reports of carb trouble, and apparently ONAN didn't design in a FUEL DRAIN, and they're selling carbs like donuts for $395 a crack. Not impressive.

This is my first RV with a gennie, and so far I'm aghast! Looking into alternatives.....

SLOweather · 09-02-2020, 05:43 PM

No indication that you have followed the recommendations to run the generator under load for an hour once a month...

al1florida · 09-02-2020, 05:57 PM

If you don't run the generator every month for 30 minutes to an hour under a load (air conditioner) with fresh gasoline in the tank it will gum up the carburetor.

If you store the RV for more than a month you must put Stabil in the fuel tank and run the engine and generator long enough to get the stabilized fuel through out the system.

Keep in mind just dumping in the Stabil in the tank and then running the engines won't do the job. You need to drive long enough to slosh the fuel around to get the Stabil to mix in.

DesertRatt · 09-02-2020, 07:13 PM

Quote:

Originally Posted by SLOweather

No indication that you have followed the recommendations to run the generator under load for an hour once a month...

Right. I just bought this RV. It's a 2004 with 12,000 miles. I've had it about a month just doing all the repairs: tires, shocks, sway bars, batteries, oil changes, back up camera, interior work, etc. I have no idea how the unit was maintained before I got it, but.....I believe the owners were very old, and parked it for a few years before some flippers bought it and sold it to me.

AveryF · 09-05-2020, 08:55 PM

We purchased a 2004 Itasca Sunrise last year from my wife’s aunt and uncle who are getting up in years and are physically unable to travel. Anyway, to make a long story short, the carburetor in the Onan generator was gummed to the point that two cans of Seafoam didn’t even help. I decided to roll the dice and get an inexpensive knock-off on eBay and it’s purred like a kitten since!

DesertRatt · 09-06-2020, 06:18 AM

Quote:

Originally Posted by AveryF

We purchased a 2004 Itasca Sunrise last year from my wife’s aunt and uncle who are getting up in years and are physically unable to travel. Anyway, to make a long story short, the carburetor in the Onan generator was gummed to the point that two cans of Seafoam didn’t even help. I decided to roll the dice and get an inexpensive knock-off on eBay and it’s purred like a kitten since!

Yes, for $45 versus $900 is sounds like a good bet to me. We've been getting ready for our first trip, which won't need a gennie, so I let it go for now. But, when we get back next week, I'm going to try one of those Ebay carbs.

09 harley · 09-06-2020, 04:55 PM

The solution is to prevent the problem in the first place. The problem is the ethanol in the fuel. The solution is to purchase non ethanol fuel. They are not hard to find. Buy 5 gallons at a time and you should be able to find it during your travels. I use it for all yard, garden, and any small engine I have and I have never had a carburetor related problem. You can thank our leaders for this crazy idea.

DesertRatt · 09-06-2020, 05:10 PM

I live in California, I rarely if ever see ethanol gas here. BTW, I just bought this RV 6 weeks ago. While in my care, it will be maintained!

CAPTAINJIM · 09-06-2020, 05:21 PM

Quote:

Originally Posted by desertratt

my 2004 e/450 minnie winnie has the infamous "onan carb clog". Dang!

First problem: Getting a new one is near impossible. I've been waiting weeks for a back ordered one to arrive at my fixit shop.

Second problem: He want's the astronomical sum of $992.00 for the carb and installation!

So, after doing the usual online snooping, i find out a few things. Ebay has replacements for $35, but apparently, they are junk and not worthy of the task compared to the $395 oem cummins part. Sumpin' is fishy in denmark!

I've watched sever utubes about cleaning stuck carbs, with seafoam(?) etc, etc.(see:

https://www.youtube.com/watch?v=wx6pbh7hemu

)
i've watched utubes about replacing them with the new oem carb.

So, now i'm thinking....maybe this is a diy project after all, and i can avoid this monster repair bill.

Anyone with direct experience on these things? My inclination is to pull the whole thing out and rebuild the entire generator to new condition, or alternately, replace it without something more reliable.

Thoughts?

carb soak in quarts or gallons at napa

CAPTAINJIM · 09-06-2020, 05:24 PM

Get carb soaking cleaner at napa, submerge it a couple days

remove it blow it out, replace and start generator

Morich · 09-06-2020, 05:39 PM

While it is always popular to blame something on somebody they don't like, carb fouling blamed on ethanol is not very accurate as carb fouling has been around as long as carbs have been used!
We used to tear the old 53 Ford down every once in a while and clean the carb and that was way before ethanol in gasoline.

JoeC · 09-06-2020, 05:58 PM

When today's gasoline sits around in the carb for a while, a nice sticky green gunk starts to form. One way to PREVENT issues like this one, use "Startron" in your tank periodically, especially before storage and run the generator to make sure the additive makes it all the way to the carburetor before shutting down. This stuff has an enzyme in it that eats the crud that collects in the stagnant gasoline. You can also drain the float bowl on the generator before storing it for any length of time. Startron will also help your big engine run better too. One bottle is good for a 40 gallon tank, if my memory serves me correctly. I use Startron for all of my small engines at home too. Available at many big box and hardware stores for around $7.00 a bottle. A lot cheaper than a new carb or repair job.

e4services · 09-06-2020, 06:03 PM

My experience with this generator as a repairman is the idle jet becomes chock and even blinded from the alcohol on the fuel. If you pull the bowl, the jet is right there. Unscrew it and take it out. You will need to find a wire the right size to JAMB through there. This is a problem with motorcycles too. THe carbs just are not design to deal with alcohol fuel.
If you do not keep it running, the water the alcohol attracts causes some sort of inter-material corrosion

Cr250 · 09-06-2020, 06:28 PM

The problem isn't the generator, it's the way its stored. While Stabile is good, Startron is way better, stores fuel for up to 2 years. A gallon of it is $90, treats I believe 2400 gallons. The other thing with these, put a fuel shut off in the line or simply cut power to the fuel pump, let it run till it dies. No fuel = no clogged jets. Ya you will probably still have to clean the carb. Good luck.

DesertRatt · 09-06-2020, 07:56 PM

Quote:

Originally Posted by e4services

My experience with this generator as a repairman is the idle jet becomes chock and even blinded from the alcohol on the fuel. If you pull the bowl, the jet is right there. Unscrew it and take it out. You will need to find a wire the right size to JAMB through there. This is a problem with motorcycles too. THe carbs just are not design to deal with alcohol fuel.
If you do not keep it running, the water the alcohol attracts causes some sort of inter-material corrosion

The gen starts right up, but only runs about 10-seconds. It races up to high rpm, then drifts down to try to idle, the goes up a few hundred rpm and shuts off.

If the "jet" was blocked, would it start?

Kickenrock · 09-06-2020, 08:08 PM

Genuine Onan carburetor is available on Amazon for less than $300. See the link below. Anyone with any mechanical skills should be able to change the carb in an hour or less. So $600 for installation is excessive. On the carb you will see a Philips head screw and spring just below the altitude compensation adjuster. When you are storing your MH open that screw, it will drain the gas from the carb. I do that on my Onan 5500 and have never had a problem with my generator.

https://www.amazon.com/Cummins-14607...s%2C748&sr=8-5

Bill