Onan 5500 generator won't start

[goin2drt]

Can a so-so mechanical person get some advice here?

Above gen in a Georgetown 329. Really low hours, gen not used much as we have been going to full hook ups lately.

It just turns over and over and won't fire. Before taking it in or having a pro look at it, are there some basic things I can do or check?

I am ok mechanically inclined but never on a generator, actually have never even taken off the cover.

[mlatter]

How much fuel in your tank? I had a MH a while back that would not run the generator if the fuel level was below a quarter or so.

[bob dirt]

also make sure your oil level is up. Some generators have a low oil safety switch

[goin2drt]

3/4 fuel so that shouldn't be an issue.

I will check the oil.

[jeffster]

Hopefully it is something simple, but I just had to replace the carb on my 9 month old Onan 4K with 30 hours due to varnishing. I always use treated fuel and I have never had an issue with any power tools, snowmobiles or my side by side when using the same fuel, but apparently the passages are so small in these throw away carbs Onan uses, it is common (you can't buy a rebuild kit for these carbs, so it literally is a throw away and replace). So, $344 later I am back in business. Took me maybe 20 minutes to swap it, so not sure how much labor would have been to have them do it. The guy at Cummins told me they are now recommending the Onans to be run every 2 weeks under load for 30 minutes. To me that is just ridiculous, but I also don't feel like shelling out hundreds of dollars every 9 months either...

[zookie]

You could try a shot of starting fluid to see if it fires. Other poster was correct the venturi are very small and clog fast with the crap we are buying at the pump. I always started and ran the granny for about 30 minutes per month with a load and almost always add seafoam to my tank.
They can be very costly if not exercised regularly..

[rvrobocop]

I can only offer my own experiences. Onan 4000 religiously run 2 hours every month under load. Have only changed the oil once in 6 years. Never have had a problem from day one. Same with my stand alone Champion 9000.

[Wattsworld]

Originally Posted by goin2drt

Can a so-so mechanical person get some advice here?

Above gen in a Georgetown 329. Really low hours, gen not used much as we have been going to full hook ups lately.

It just turns over and over and won't fire. Before taking it in or having a pro look at it, are there some basic things I can do or check?

I am ok mechanically inclined but never on a generator, actually have never even taken off the cover.

Did you ever get this generator to run? Did this happen all at once after using it, or has it been setting for awhile?
If it has been setting for awhile, you might need to prime it longer. If it has been setting for some time then it might be gummed up as others have said.
make sure it is getting fuel, that the tank is 1/3 full or more.

[Joe_GA]

I had a whole house generator when I lived in Georgia. It was set up to run for 10 minutes every Saturday and it ran on natural gas. You have to run gasoline generators frequently.

[goin2drt]

So the latest and to answer a few questions.

Gas genny has 20 hrs on it. It has been sitting since last running about 9 months (I now know not to do that)

I shot engine starter in the carb. It fires up and runs for maybe 2-3 seconds and dies again.

[goin2drt]

And tank is 3/4 full

[PenJoe]

Originally Posted by zookie

You could try a shot of starting fluid to see if it fires. Other poster was correct the venturi are very small and clog fast with the crap we are buying at the pump. I always started and ran the granny for about 30 minutes per month with a load and almost always add seafoam to my tank.
They can be very costly if not exercised regularly..

Personally, I would not suggest starter fluid for anything. For year, as many as I can remember, I have successfully started gas engines with WD 40. It lubricates the cylinder walls, ignites better than gasoline and won't lift the heads off the motor if you spray too much.

Recently, we could not start our generator after being dormant for a long time. Here is what we did to get it running. Once it started, we shut it down and restarted. It ran fine. Here is what we did:

1.Open the bay door and remove the generator side panel.
2. On the left side is the carb. and air cleaner. Remove the air cleaner housing and air cleaner. With the little red straw on the can of WD 40, spray a dose of WD 40 into the carb with the choke open.
3. Allowing the choke to go back to its position, turn the generator over in about five seconds so it does not overheat the starter.
4. If it doesn't pop after a half dozen tries, spray another dose of WD 40 into the carb throat and repeat step 3. It helps if there is a second person manually working the choke.

When we did this, the generator started and ran smoothly. What happens when an engine sits is two things. The gas in the carb evaporates and may gum a little. The cylinder walls will also dry so that the piston is not sucking gas. The WD 40 is a lubricant that vaporizes rapidly and is volatile, but not explosive.

[goin2drt]

Tried WD40. Wont fire at all. With the engine starter it fires for a few seconds.

I will need to see what entails to find the gas line into the carb and hold the prime button.

Can't find it real quick so I will try again tomorrow when I have better access to the RV.

[Sharon455]

When you try to start the generator directly, the light on the starter switch flashes codes. They are listed on page 22 ( it might say 1 of 7)
https://manuals.heartlandowners.org/...ng%20Codes.pdf

[camaraderie]

Watch this video and his other one for some easy ideas on possible causes & fix.

https://www.youtube.com/watch?v=CLLI359w2RM

[Wolverine 1945]

Originally Posted by goin2drt

Can a so-so mechanical person get some advice here?

Above gen in a Georgetown 329. Really low hours, gen not used much as we have been going to full hook ups lately.

It just turns over and over and won't fire. Before taking it in or having a pro look at it, are there some basic things I can do or check?

I am ok mechanically inclined but never on a generator, actually have never even taken off the cover.

ONAN says Genny must run 1 hour each month under load,,, the Carbs in these units are very fragile,,, we just had ours replaced on a 3 year old 4k,,,
that had less than 3 hours on it !!! Because we did not use it enough !!!
If you search Generator here you will find a lot of good advice !!!
I do wish our ONAN had a gas shut-off like out house genny has !!!

[Wolverine 1945]

Originally Posted by camaraderie

Watch this video and his other one for some easy ideas on possible causes & fix.

May Be The Carburetor ???
From what I have learned it is always the Carburetor !!!

I would love to have half the money ONAN must make selling these Pic-0-Crap Carburetors !!!
Our Gentron sets in the garage for months,,, but fires up every time I test it,,,
It is a 10k with GAS SHUT OFF VALVE !!!

[JJaxon]

Very interested in this thread, and the solution. My Onan 2800 has the same issue, under similar circumstances. I got it to run, and under load ran fine. but surged at idle almost constantly. Mine had sat for at least 2 years (previous owner) and had old gas in tank nearly full. I removed the tank and drained, cleaned and reinstalled, with new fuel line (24') to the new filter. Could not access the fuel pump, but verified it works. Now nothing, so I bought the new carb and installed. Still nothing. One time during cranking it did back fire, and hasn't sounded like it wants to start, even using starting fluid. Without removing the unit from the compartment, I cant think to do much of anything to get it started. I hope you and I find the solution.

Did you ever get a backfire while cranking? Someone here mentioned "lifting the head" and I wonder if that is what they meant?

[Wolverine 1945]

Cummins will not clean these carbs,,, because of there $138 an hour labor charges it is cheaper to replace them,,, in our throw away world !!!
I am guessing,,, altho I never believed in fuel additives before fuel injection,,, with having these generators we should be using something,,, Seafoam works well in all my small engines,,, guess it is time to add to our MH !!! And maybe a shut-off valve !!!

[jaherbst]

Only problems I have had it was not primed enough. I learned that I had to hold the primer switch in with a count of 20-25 after the light goes out.The priming does not start until the light goes out. This was news to me. I always thought the light went out when it was primed.

Jack