Onan 5500 issues running reading codes and parts

porthole

Retired
I run Valvtec Ethanol Marine treatment and stabilizer in the Cyclones fuel tank - all the time. The fuel gets used throughout the tow season and a fresh tank is added coming home from the last trip of the year. In the spring all the fuel is pumped into the mower (holds 11 gallons) 5 gallon jugs and the remainder goes in the car. Then fresh fuel added to the Cyclone, with treatment.

Once a month the genny is started, allowed to warm up then run for about 30 minutes under a load, 2 heat strips in AC units and a 1500 watt Pelonis. A 5 minute cool down period and then shut down. I figure this is about the best you can do with a gasoline generator. I do the same with my Honda 3000.

Night before leaving for a week of boon-docking at Dover the Onan would not run well. Changed the fuel filter and called it a night. From past experience I learned that if you have a good portable genny and the means to bring it along, you may as well, so the Honda was already in the trailer.

At Dover - 90 degrees and the Onan runs poor. Bad enough with "hunting" and shutting down that I thought it may have damaged our main AC (another thread). Great, 1st day of a week trip and 1 AC down and 1 generator down, both primary units.

Used the bedroom AC, the Honda and 2 12 volt portable Fantastic fans. The trailer already has multiple 12 volt outlets added for areas where we can't run genny's.

The Onan throws codes for certain issues. Removing the cover gains access to a manual switch and circuit breakers. The switch may or may not be flashing red.

If flashing it should be 3 flashes followed by a pause. This indicates a stored fault code. one push of the switch will generate the sequence. For example; 3 flashes - pause - 6 flashes - for a code 36. This will repeat until you press the switch again, which will clear the stored codes.

If the switch is not flashing but there are stored codes you press the switch off 3 times, then the codes will start.

36 is a common code and the list of troubleshooting is long and pretty much covers every possible outcome. Including a fuel control solenoid replacement.

I want to take the carb apart and look inside. Turns out there are 2 Onan dealers within 5 miles of Dover Speedway.

Both dealers gave me pretty much the same information.
Mine is a common problem.
Onan no longer supplies any carb related parts, e.g. the gaskets and the fuel control solenoid.
You can now only buy a complete carb assembly for $250.

One of the dealers suggested that if the jets were clogged one way to help clear it would be to get it running a full speed and manually close the choke, forcing the pulling of fuel through the jets and vents. Reminds me of one of the tricks we use to do back in the late 70's, early 80's when fuel started to cause havoc with automobile carbs.

Neither dealer knew anything about any recall on the fuel pump when I gave them the number.

Back to the trailer to try once again. The Onan starts and runs great for the next 8 hours. Same thing the next day.
3rd day it acts up, will not come up to speed, sputters and stalls etc.

One of the steps for code 36 is replacing the fuel control solenoid, you can't buy one so I did the next best thing - rapped it with a wrench several times. Runs smooth as butter now. Ran good for 2 days and acted up on the last day. Rapped the solenoid once again and it ran smooth.
 
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danemayer

Moderator
Staff member
A time tested technique. When all else fails, pull out the 16 ounce "persuader".


Sent from my iPad using Tapatalk HD
 

porthole

Retired
Here is the solenoid, silver object with the two white wires coming out the bottom.

BTW, older 5500's have two fuel filters, same filter, so the 2nd is really useless. Onan has since bypassed it.
If you have a 2 filter model there is a replacement fitting to remove it, part number A026E529

In the same picture, the adapter is the silver object with red paint on it, rubber hose attached to the bottom.
This is where the 2nd filter would be if equipped.

The solenoid is above and to the left of the yellow plug, white connector on the bottom of it.
 

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Sandpirate69

Well-known member
But would that solenoid cause the surging? I can see how the ethanol deteriorates fuel lines & cause main or idle jets to get clogged. But it runs awsome under load. So I'm a bit stumped by it.
 

porthole

Retired
But would that solenoid cause the surging?


Yes it does. Under no load the genny could be drawing just enough fuel past any sticking plunger or debris to run, surging, hunting etc.
Under a load, the fuel draw may be enough to overcome a sticking plunger.

Either way with your issue (same symptoms as mine) doesn't cost anything to try.

I was ready to buy a $250 carb assembly at Dover last year until I tried the "rap" method.
 

Sandpirate69

Well-known member
"Rap" please explain this procedure. Rap to me means hit it with something to dislodge. Not sure if that's what you mean by "Rap". Please advise
Thank you
 

porthole

Retired
"Rap" please explain this procedure. Rap to me means hit it with something to dislodge. Not sure if that's what you mean by "Rap". Please advise
Thank you


Tap the side of the solenoid with a solid object while it is running, preferably when it is not running correctly.
I used the same wrench I had out to replace the fuel filter.
 

marcusweeks

Member
I ran mine yesterday, under no load it ran for 2-3 minutes then started surging up and down until finally stalling. Until then it ran smooth. I've noticed the gas is very yellow looking. It came from texas, I was thinking it was an ethanol colored gas. Would an 09 Onan show codes as described with the off switch? That way if no codes are shown, I'll remove the fuel and replace the filter and see if it helps. It's hard to run it under a good load now, winters here, the ac units are covered in snow. One other thing, my fuel gauge has never worked, always on empty. Anyone else had this problem?
 

porthole

Retired
If you don't know the condition - age of your fuel, I would dump all of it.
Start with a fresh tank, add SeaFoam treatment and perhaps ValvTec's ethanol fuel treatment.

Get the genny running, then put it under a load, use electric heaters, at least one on each leg.
Run for about an hour.

When time is up, turn off all loads and let genny run on a cool down mode for 5 minutes.
 

marcusweeks

Member
Thanks, I never thought of doing it that way.I thought about putting in a space heater, but I was thinking that all the outlets were on the same breaker, not thinking of plugging into the refrigerator outlet, wine cooler outlet ect. my son will definitely be excited, free gas for a month, lol! if needed, where would a good place be to get a fuel filter?
 

porthole

Retired
Fuel filters - Onan dealer, Camping World, Amazon or eBay.

I may have a spare in the trailer, I'll check tomorrow for the part number.
 

porthole

Retired
OK, scratch the above, I have this on my phone

Onan parts for the 5.5

Onan - 5.5HGJAB-901A


Oil filter 122-0836
Air filter 140-3116
Fuel filter 149-2341-01
Spark Plugs 167-1638
Fuel pump A029F887
Carb 0531 0765


Adapter, Fuel Line #A026E529 $18.06 replaces the upper fuel filter


thin wall oil filter removal tool (not really needed)
420-0577 $6.18


2 quarts oil with filter
10w-30 0-80
15w-40 10-100
30w 32 and higher


adapter old style part
#0149-2629
 

marcusweeks

Member
thanks, I did some investigating myself, and found the location of the fuel filter, and found it on eBay. I'm going to stop by Camping World this weekend, if they don't have it I'll just order it. I did do an oil change on it already, which I think it was the first time, and used a Baldwin filter and synthetic 5w 40 oil. basically looking at the condition of everything else, I think the fuel filter is original too.
 

marcusweeks

Member
I went to camping world this past weekend. as I figured they had nothing in stock, except four quarts of oil. Waiting for the UPS truck to show up now. And almost got all the old gas out.I checked for codes, and it brought up the 3-6 code. Which could be fuel filter issue.
 

porthole

Retired
The 3-6 code covers just about every possible problem with the genny. I think I may have a copy of the codes from the dealer. I'll check later today.
 

marcusweeks

Member
I downloaded the owners manual, and it does basically cover everything. If it drops below 1000 rpms for a second, it triggers a code. Of course it doesn't tell you how to fix it
 

porthole

Retired
Before this past weekend's Dover race I added one can of SeaFoam to the Cyclone's tank. The fuel always has Valvtect ethanol and stabilizer treatment added. After the first 6-8 hours the genny stopped with it's snarkey running and did well for the next 4 days running everything in the rig. It did require two applications of an appropriately placed rap on the solenoid before it smoothened out.

http://seafoamsales.com/sea-foam-motor-treatment/

http://www.valvtect.com/marineGasAdditives.asp
 
Re: Onan 5500 issues running / reading codes 36 and parts

Hi all Im new to this forum, thankfully I found in a net search. I have a onan 5500 mounted in my 2010 fusion, have been running very strong, until a couple days ago. I went to start it and it started ran for a second and shut down, tried cranking it again and fuel started dripping out of the air filter cover. the fault code is 36, :mad:That could be a number of things, anyone ever have this problem?? Thanks in advance for any help you can offer.
I did remove the air filter, and once again crank it over to see plenty of fuel pumping , to much I believe its flooding out.
 

danemayer

Moderator
Staff member
Re: Onan 5500 issues running / reading codes 36 and parts

Hi all Im new to this forum, thankfully I found in a net search. I have a onan 5500 mounted in my 2010 fusion, have been running very strong, until a couple days ago. I went to start it and it started ran for a second and shut down, tried cranking it again and fuel started dripping out of the air filter cover. the fault code is 36, :mad:That could be a number of things, anyone ever have this problem?? Thanks in advance for any help you can offer.
I did remove the air filter, and once again crank it over to see plenty of fuel pumping , to much I believe its flooding out.


Hi hualinharleys,

Welcome to the Heartland Owners Forum. I think we have a few Heartland owners here who have solved problems on their generators, although I don't recall any specific discussion about fault code 36. Maybe someone will chime in.

I did find the following suggestions from Onan.

ENGINE STOPPED FAULT—CODE NO. 36
(Engine stopped without command by controller)
Corrective Action:
1. Gasoline Models – Check and fill the fuel tank, as necessary. (Note: The genset fuel pickup tube
is probably higher up in the fuel tank than the vehicle engine pickup.)
2. Low Pressure LPG Models – Check and fill the LPG container, as necessary. On cold days the LPG
container may have to be kept at least half full to provide the rate of vaporization necessary to keep
up with the genset fuel demand.
3. High Pressure LPG Models – Check and fill the LPG container, as necessary, and drain the genset
LPG system of oil that may have migrated from the supply system (Item 5, Page 13). Make sure to
re-close the drain valve.
4. Secure the spark plug leads on the spark plugs (Page 20).
5. Replace the spark plugs (Page 20).
6. Service the air cleaner (Page 19).
7. Check for mechanical damage.
 
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