Onan 2800 Generator

After searching I have found the schematic for the one I have which is about 20 years old. Reading these things is always a challenge and quite frankly even though I studied it before it was like the first time I ever looked at it. The one I have does show a magneto going to a coil for the spark plug. It doesn't look like points and condenser or module are used to produce the AC needed to transform low voltage to high voltage. Or at least the schematic didn't show them. I don't know if any magneto uses them or if they produce a wave or broken form of electric. All I know is you can't transform DC volts it must be converted to something like a wave form.
With this additional info I still cannot say what is wrong with the original posters problem. If it would be the same as mine I would still consider the control board but with so many models there can be many other factors too that I never had experience or could imagine.

AFAIK, the ignition voltage comes from the 120V windings, but that's a part I've never had reason to figure out (yet ;)). They'd need to step it up to around 10kV or more for a spark plug. Again AFAIK, there's no separate winding or magneto.

The reason there's a delay in your 120V is not in the generator. I think it's in the transfer switch. My Tiger hasn't got one, and the 120V inside is live as soon as the Onan starts. Some RV makers choose to set up a delay to be insure the Onan is up to speed before any load is applied, others trust the customer not to start the Onan with the A/C switched on.

Clear as mud, right? ;) I've been futzing about with these dang things for about 12 years & three 2800's now; it's been a long, slow learning curve with some dips along the way.

Jim, "Why do gas stations lock their restrooms? Are they afraid someone will sneak in and clean them?"

Handbasket wrote:
g1g, the small Onans get their ignition voltage from the battery while they're cranking. But they switch over to self-generated voltage from the generator section when the start switch is let up. If they don't get it, they shut off. Failures can be caused by oil level sensor if fitted, rotor/stator issues, brushes, or control board / voltage regulator.

Jim, "Is your computer possessed? Try Exor.sys!"

OK i didn't know that and there can be multiple ways for that to happen. Does the juice come from the 120v generator or from someplace else like a magneto? Or possibly a 12v winding on the genny.
On Jim and Carolyn's post if the power comes from the 120v genny I can understand if bad windings cause this, according to what you said, but my 120v doesn't kick in until after about 10-15 seconds of running after I let go of my start switch. With the limited info mentioned the problem could be the same as what happened to me where a relay went bad. Possibly the relay is what switched power to the run position, from wherever it gets its power.
Jim, "Is your computer possessed? Try Exor.sys!"

I have to mention this to you ,Handbag, I have seen many of your post along with a few others, i know you and a few more experienced people, know what you are talking about. I could learn a lot picking your brains. I'm relatively a beginner myself and I appreciate good information.

I just found a place that says they have worked on many Onan generators as part of their RV service. He certainly had the right answers so I just dropped it off - only about 50 miles from my place. Should get some kind of report in the next few days.

handbasket wrote:
Do you know if the dealer checked the windings with a meter by unplugging the big multiwire white connecter? If he just asked the symptoms and came up with that, you may be taken for a $$$ ride.

Yes, I saw the tech working on the unit but can't tell you exactly what he did.

I'm really not a mechanic so things that everyone is suggesting is very foreign to me. Which is why I though maybe I could find a good used one and install it.

g1g, the small Onans get their ignition voltage from the battery while they're cranking. But they switch over to self-generated voltage from the generator section when the start switch is let up. If they don't get it, they shut off. Failures can be caused by oil level sensor if fitted, rotor/stator issues, brushes, or control board / voltage regulator.

Jim, "Is your computer possessed? Try Exor.sys!"

I'm by far no expert but I don't see how the generator part won't let it run. When I fixed mine I probably got advice and parts the same place as you and it didn't work. Mine did that for a bit then it would only start when the van motor was running then it wouldn't start at all. Originally thought it was a bad solenoid. I ended up changing the control board and it is fine. I got it from I think Flight System?? in PA. I found out there were a couple bad relays on it. I can't say that is your problem but i would check it and more before replacing the entire thing.

Do you know if the dealer checked the windings with a meter by unplugging the big multiwire white connecter? If he just asked the symptoms and came up with that, you may be taken for a $$$ ride.

I ask because while that is the worst $$ way the gen can fail suddenly, there's at least one other way (voltage reg, easy fix, one hidden screw, about $250 part). And believe me, I know your frustration! They completely rebuilt the electrical part of mine under warranty due to a similar failure at _8_ hours. IIRC, Onan was billed about $1600 for that. That's when they left the bolt loose and left a mount out.

And yes, you may have a low oil float switch as retraite said. They discontinued that sometime in the past, but I don't have a clue as to when. And it _will_ give the same symptom. If you have an owner's manual, read the proper procedure for checking oil. Mine ('06) requires you to remove & wipe the dipstick, then set it on the hole, not screwed in, to check the level. Screwing it in before reading will give a false reading resulting in low oil.

And trust me, I'm not particularly wrench savvy, just persistent... ;)

Jim, "No, the other one."

Jim&Carolyn wrote:
I took this thing to a Cummins Onan dealer and they told me the windings were bad and couldn't be repaired and wanted to sell me a new one. I just didn't believe them when the thing had been running so good. It's just that now it only runs when I continue to hold the switch down and even then it doesn't output the current I need. I dropped it and took it to a electrical shop but they can't figure it out.

Jim,

Exactly the problem I had a few years ago - had to hold the switch down so it would "run". An earlier oil change used the incorrect mark on the dipstick.

The problem was the oil level. My unit, like most I think, seems to be quite picky on that point. Filled 'er up (two or three tablespoons of oil) and fine ever since. Now we're careful on oil changes.

But, it could be something else.

My suggestion within Onan is to ask to talk with the tech first. I went in my car, it took some persuading, but I did get to the tech for a question or two. He did understand, I took the rig a few days later, they confirmed the issue, and I both paid the bill and found the tech again to say "Thank$".

Cheers.

I took this thing to a Cummins Onan dealer and they told me the windings were bad and couldn't be repaired and wanted to sell me a new one. I just didn't believe them when the thing had been running so good. It's just that now it only runs when I continue to hold the switch down and even then it doesn't output the current I need. I dropped it and took it to a electrical shop but they can't figure it out.