RobG

My 5th wheel has an Onan 5500 Marquis generator (gasoline). It has about 200 hours on it. It's having a Code 13 error, and I've done some diagnosis to fix it, but it's to the point that I have to remove the generator from the trailer to continue the process. I'm not really in the mood to fool with it and am thinking about just putting an ad up on Craigslist that tells about it, the error code, and if they come remove it, they can have it for $xxx. I just need to know what $xxx might be.

Any thoughts?

The plan is to weld up a tray that slides in and out of the compartment and I'll buy a cheaper generator to go in its place. The output won't be as high, but I don't need it to be.

bobsallyh

Rob, where are you located? Will it start, then puke, cough, etc. Or just no start at all? The carburetor on these things are absolute junk. I have the Marquis 7000 and they are basically the same.

RobG

I'm in Salem, Oregon.

It'll fire up but then dies within a minute and starts flashing the code that says there's a code. So I follow the steps to pull the code and it's a 13.

The carb has been cleaned. It was even running fairly okay a couple months ago as long as you didn't put a full load on it. But then it just got to where it won't stay running. I've confirmed it's getting enough fuel.

As I recall.. it's been a while since I fooled with it... it'd run fine, then every couple of minutes it'd start blowing black smoke out the exhaust. It'd do this for about 30-60 seconds, then go back to running fine for 2-3 minutes. Rinse and repeat. This is even with a 5-gal jug of 100% fresh gas and a tube running into it from the low-pressure fuel pump. It's just weird that it does that almost like clockwork, so it doesn't seem like a carb issue.

KATOOM

Code 13 pertains to voltage from the generator not the engine so you're either seeing that code because the engine isnt running correctly or there's something wrong with the generator. Given how ridiculously common it is for people to let their generators sit for months and months at a time without ever being started, its most likely a fuel issue and/or a carburetor issue.

Just pointing out that "cleaning" a carburetor pertains to a lot more than just running a chemical through it or spraying off the large easily accessible orifices with carb cleaner. The real problem is that todays fuels have ethanol in them and ethanol is hygroscopic which means it attracts and absorbs water. Thats not good because ethanol also phase separates much faster than older type gasoline fuels and will varnish leaving hard deposits that eventually plug small ports. Obviously thats all bad for carburetors and will mess things up in a hurry if you let your engines sit unattended for long periods of time.

Actually what you NEED to do is make sure you always use Sta-bil "marine" in your trailers fuel tank. "Marine" version will help more with water which will help a lot.....

So if you already haven't, I'd suggest taking off the carburetor and completely disassembling it. Use carb cleaner, an air compressor, and a very small firm wire to chase out all the small ports and orifices. Then check to make sure the electric fuel shut off solenoid valve is working appropriately as well.

Put everything back together making sure you put all mixture screws back EXACTLY the way they came out and with the correct number of turns so you dont change any air/fuel ratios. Upon doing all that I'm sure you'll find your generator will run nice..... Actually not to long ago another member had the same issue and eventually fixed it after doing everything just mentioned.

RobG

Well, fwiw, I've always kept stabilizer in the tank and made a point of running it monthly to avoid that problem. I replaced the carb once back in 2009 because I forgot and it got all gummed up and everybody told me it wasn't serviceable (I've since discovered otherwise).

I'll go ahead and give it a try though... I'll disassemble it and soak it and stuff and see if that helps.

KATOOM

Dont forget to use the small diameter wire and poke around in all the small orifices/jets. Sometimes they look clear until you realize you cant get the wire through them because of a clog.

bobsallyh

Having been down this road, here is my story. Generator is either used or exercised every month. Gas always has Stabil Marine or Seafoam in it. With about approx. 150 hours on the clock it started puking, popping, wanting to stall when more juice was called for ie: water heater kicks on, AC kicks on. So I did some R&D on the internet and the unit itself. Everything led towards the carb and of course Code 13. So coming into Kalispell, MT. I saw an RV joint that had an Onan shingle hanging outside. Didn't disappoint me because as usual they just had oil filters spark plugs etc. But they told me about a small engine repair place just down the road that did Onan work. So I stop there and a young gal at the counter listened to my story. She says "just a minute, I'll get my husband who does the Onan work". Nice guy comes out and I repeat my story. "It is the carb, yes todays gas doesn't help, but the carbs are not rebuildable as there is no kit and they are junk. I just put one on last week for a guy, I had to get it out of Seattle and their inventory showed one more. He calls them and that one was gone". So we weren't staying in the area I thanked him for his time and info. He did say that if I was going thru Missoula I could call Rock Mountain Onan and check to see if they had any in stock but also said he doubts they would. So I call RMO, no dice. So we continue on our journey and stop in Idaho Falls, ID. for a couple days. There is a nice RV supply place there, State Trailer Supply, that I remembered also had the Onan shingle out side. Same deal, plugs Fiters and the like. But the guy sent me 1/4 mile around the corner to a diesel and Onan shop. Went in, parts counter guy asked what I needed. Told him I needed a carb for a Marquise 7000 and started to give him the part number. He spit out the part number before I even got going good! He says" I usually have FOUR in stock. Just a minute I'll be back. if you take this I'm down to THREE. Genny puking?" "Yep, that is what it is doing" "Well if a genny comes in here for that problem, within 15 minutes the tech will be here taking a carb." They can blame the gas but the carbs are junk". So $192.00 I'm on my way. Changed it out next day and ran like a top. After taking it off, I R&R'ed it. It is definitely a throw away unit. No rebuilts on the market, no rebuildabe kits either. Fast forward to now, five years later. Starting a repeat performance. I'm like you Rob, this thing could become a boat anchor, of course after draining the fluids, real darn quick. I'm in the Vegas area now, was hoping you were nearby. I may blame the gas just a little, but how come these guys with the Hondas and Yamahawzees from the 1000 up to 6500 or whatever size it is, they pull or electric start, and hum along they go. I sure haven't seen Onan jump into this market area! I wonder why? Maybe if they put Honda or Yamahawzee motors on them we wouldn't be having this discussion. Maybe if they put Honda or Yamahzee motors on them we wouldn't be having this discussion.

patdaly

Perhaps just put a Honda carb on your Onan?

KATOOM

Not sure thats an option.

SIXSLUG

I've switched all our small stuff to hand for the same reason...carbs are easy to tune up...

bobsallyh

If Onan would swallow some pride and just put a Honda motor on their gennys it would solve the problems. I think they do use a Kubota on their diesel gennys. It reminds me of GM in the late 70's and thru the 80's trying to do their own diesel program in light trucks. We all know that story. I never had problems with the electrical generation part of an Onan.

KATOOM

Mmmm..... I'm not sure its an "engine" problem as much as its just a "fuel" problem. Onan is Cummins and as much as I dont have a problem with Honda, I'm not sure I'd make the claim that they make anything better.

Simply put, dont let your generators sit for months on end and they should run fine. But try running a pole asking how many people actually take the time starting their generators every month or so and I'm betting the results show obvious reasons why people have trouble with their generators.

bobsallyh

Yesterday, Friday, was a great Onan day. We are in an RV park in Boulder City, NV. (Vegas) and where I sit in my chair outside I can watch the entrance to a very busy auto repair business. Last week they brought a Bounder motorhome in on the "hook". On Wednesday it looked like they started on it. Looked like they were doing something under the rear end. Then later that afternoon it was on the move in their work yard. They then parked it for the evening. Yesterday morning they opened the hood and were working on something that looked to be on the front of the motor. While I was reading the morning paper I heard a familiar sound, that of an Onan trying to start.The shop owner who is a professional mechanic was trying to start, you know what in a side bay. Unnhh, unnhh, unnhh, you know the pathetic sound. Shortly after, it is running, yep, but wait, she shuts down. A couple more times and the usual puking and choking. He walks away from it, comes back about an hour later, same story. He then walked towards their office and I thought he may be ordering parts. Back to the genny about 2 hours, tries again and tapping on the fuel bowl. No luck. I'm sure he smelled the fuel and was why he waited between sessions and aggravation. He walks away from it with looks and a walk like I do when POed. He did have much more patience than I have. Now getting toward closing time and the bay door goes closed. We are still going to be here Monday so maybe there will be something new to report. I was getting very close to walk over and tell him the best thing he could do to solve the problem, would be yank it out of the bay, drain all the fluids out of it, load it on his truck, drive out to Lake Mead and find a boater that was in need of a boat anchor! KATOOM, I thought when Cummins bought into Onan things would improve but that sure isn't the case unfortunately.

RobG

Hahahaha. Sad thing is you're probably right.

I need to find the time to do a good cleaning on my carb and see if it fixes it per another poster's suggestion. If it doesn't, I may try to find somebody to give me $500 for it, then I'll just go buy a small Honda or something that'll run the microwave and call it good. Or invest the money in more solar panels and batteries.

KATOOM

bobsallyh dont mistake my point and opinions..... I have no love for "Onan", nor do I defend them for any other reason other to make claim that Onan isnt the problem, rather its the people who own them.....

And from your last experience it sounds like you had the opportune time to disprove me too by simply walking up to that poor fellow and not only make his day by asking him if he needed a hand, but to find out why his generator isnt working. I would probably be very comfortable betting a brand new crispy dollar bill that his response to your inquiry would have been something along the lines of "well it ran fine last summer". And probably including a bonus statement of something like, "I know its full of fuel because I hardly ran it last season".....

Simply put, people just dont understand the inner workings of things like engines. Thats no discredit to the average folks either but more just saying that most people dont have the time or wherewithal to care about tedious complicated things. All they want is their stuff to work when they want it and preventative maintenance is generally the last thing on their minds.

Perfect example is how people treat their boats. How many people have you seen who leave their boats out in the open weather all year long? Collecting leaves, dust, bird poop, and UV rays bombarding everything nice.....only to hook it up and let the crud blow out as they head to the lake when summer arrives. Then they find themselves struggling at the launch ramps cranking away from fuel gone bad or batteries gone dead or lost drain plugs, etc... Its almost comical to sit there at the lake ramps and watch the fiascos take place. But.....it happens every year.

So again, you can call Onan generators garbage all you want but you cant deny the facts that people just treat them like crap.....so no matter how quality the component is, by treating them with such crappy love they can expect crap results.