Joe

[Joe]

The Onan 2800 in my B would run for 15 to 20 minuets then hunt for a few then quit. I changed the air and gasoline filters but still quit. I noticed it seemed to be running hot when it stopped. I accidentally left the camper hatch door open during a test run. Generator ran for hours! There is a large ovel screen vent in the door and I never had to leave it open. What could have changed?

[rowiebowie]

That does sound strange since the Onan should have it's own forced air cooling. However, if you can replicate this situation, then you've at least found a solution. Don't look a gift horse in the mouth.

I have a different problem. But similar to yours, after 10-15 minutes of purring like a kitten, my generator's problem shows up. It does not hunt or stop, but instead it cuts out momentarily like you flipped it off and back on so fast it stumbles but keeps running. So while different, my problem occurs at about the same time interval. Aggravating, and it throws the charger into fits.

[Phoebe3]

I can go for two hours, then have the same off/on/off that you have Rowiebowie. It's an Onan 2800QG (gas) model.

[Joe]

Trying new fuel pump and lines next week. Pray for the best and will advise!

[rowiebowie]

Originally Posted by Joe

Trying new fuel pump and lines next week. Pray for the best and will advise!

Thanks and yes, please post an update.

I ran my generator today and timed the instances from start, warm-up, and roof air start. Only this time I actually timed it on my phone clock. Let me add that the batteries were fully charged (just unplugged) in an attempt to take the charger amps out of the picture.

As usual, it started fine on the second attempt and ran perfectly smoothly through the 4 minute warm up (no load). Once the PCM was delivering power, I started the a/c fan and after about half a minute then started the compressor. All was smooth as silk.

After about 2 minutes running the compressor, I had the first brief cutout of the generator. It was mild and only momentary as in the past. I had the next one and several mild subsequent instances as close as 30 seconds to a little over a minute apart. But in general, the generator ran better than it has in several months. Over a total of 20 minutes run time, the instances became milder, fewer, and further apart. To the point that if this was the way the generator ran every time, I'd be satisfied.

However, it will take many more runs like this before I'll say the generator has improved since it may have just been the topped up batteries that prevented the charger from engaging harder (which it tries to do at each moderate to severe cutout).

[hepcat]

Originally Posted by rowiebowie

Thanks and yes, please post an update.

I ran my generator today and timed the instances from start, warm-up, and roof air start. But in general, the generator ran better than it has in several months. Over a total of 20 minutes run time, the instances became milder, fewer, and further apart. To the point that if this was the way the generator ran every time, I'd be satisfied.

However, it will take many more runs like this before I'll say the generator has improved since it may have just been the topped up batteries that prevented the charger from engaging harder (which it tries to do at each moderate to severe cutout).

Do you exercise it the requisite 2hrs continuous/month under a half-load?

[rowiebowie]

Originally Posted by hepcat

Do you exercise it the requisite 2hrs continuous/month under a half-load?

No I don't. I will admit it's more like 30-40 minutes every month. Sometimes I go 5-6 weeks between use. I run the roof air that pulls 12 amps on low fan according to the PCM.

I keep fresh gas in my RV and always ethanol free when I'm not away on a trip. I've heard of the 2 hrs. per month Onan recommendation, but never understood it. If I keep gas from going stale and run it 30 minutes at full operating temperature while under half a load, what other possible benefits could come from running 2 hours?

Heck, if running it more is really necessary for it's health, I guess I'm foolish not to.

[hepcat]

Originally Posted by rowiebowie

No I don't. I will admit it's more like 30-40 minutes every month. Sometimes I go 5-6 weeks between use. I run the roof air that pulls 12 amps on low fan according to the PCM.

I keep fresh gas in my RV and always ethanol free when I'm not away on a trip. I've heard of the 2 hrs. per month Onan recommendation, but never understood it. If I keep gas from going stale and run it 30 minutes at full operating temperature while under half a load, what other possible benefits could come from running 2 hours?

Heck, if running it more is really necessary for it's health, I guess I'm foolish not to.

The jets in these generators are SO small that ANY varnish can severely affect the fuel delivery. I've found that my 7.5kw Onan in the Born Free 32RQ isn't nearly as finicky as the 2800s I've had in B-Vans. After spending big bucks having carburetors and fuel pumps replaced, I've become a believer. I run my 2800 two hours continuously a month under a half load year-round. I run the AC unit in the summer and a 1200 watt space heater in the winter just to keep it exercised. In the four years I've been doing that AFTER the new carb and fuel pump I've had no issues.

I agree that it's a PITA and in a perfect world shouldn't have to be done... but it seems to make a difference.

[peteco]

Originally Posted by rowiebowie

No I don't. I will admit it's more like 30-40 minutes every month. Sometimes I go 5-6 weeks between use. I run the roof air that pulls 12 amps on low fan according to the PCM.

I keep fresh gas in my RV and always ethanol free when I'm not away on a trip. I've heard of the 2 hrs. per month Onan recommendation, but never understood it. If I keep gas from going stale and run it 30 minutes at full operating temperature while under half a load, what other possible benefits could come from running 2 hours?

Heck, if running it more is really necessary for it's health, I guess I'm foolish not to.

I exercise the generator about the same as rowiebowie. I always use fuel treatment. My favorite is Lucas fuel system treatment as I can get it cheapest from Advance Auto with online coupon. I also have used Marvel Mystery Oil and Rislone. Once a year I run Techron cleaner.

[hepcat]

Originally Posted by peteco

I exercise the generator about the same as rowiebowie. I always use fuel treatment. My favorite is Lucas fuel system treatment as I can get it cheapest from Advance Auto with online coupon. I also have used Marvel Mystery Oil and Rislone. Once a year I run Techron cleaner.

To each his own, of course. My generator guy isn't excited about additives as he says they can eat gaskets and seals if they're not mixed "as directed." When I store the big motorhome for the winter I use Seafoam and run it through the system (including the generator) as a fuel stabilizer.

I don't do anything special for the 2800. And of course, the Interstate I have now has an LP 2800 now, so the fuel is what it is.

[rowiebowie]

As I said, I've been foolish to not do the 2 hrs/month exercise. While I still don't know why 1 hour twice a month wouldn't be better or why 30 minutes is not enough, it's Onan's recommendation. They should know their product.

Further, it's not hard to do, gas consumption is negligible, and it doesn't significantly affect the oil change schedule since I believe oil should be changed annually in spite of run time. So I'm complaining about the functioning of my gen set while not following manufacturer's recommendations.

I will try and repeat my results from today with batteries fully charged and then again with batteries a little low. If the former is better than the latter, I can live with the smaller blips in operation. A bonus would be if running it in 2 hour stretches and more frequently reduces the problem.

[dicktill]

Originally Posted by rowiebowie

No I don't. I will admit it's more like 30-40 minutes every month. Sometimes I go 5-6 weeks between use. I run the roof air that pulls 12 amps on low fan according to the PCM.

I keep fresh gas in my RV and always ethanol free when I'm not away on a trip. I've heard of the 2 hrs. per month Onan recommendation, but never understood it. If I keep gas from going stale and run it 30 minutes at full operating temperature while under half a load, what other possible benefits could come from running 2 hours?

Heck, if running it more is really necessary for it's health, I guess I'm foolish not to.

There is more to it than just keeping the carburetor clean: there is the issue on all Onan's (propane too) of cleaning the oxide off the commutator. Whether the magic number is 2 hours/month is above my pay grade.

[peteco]

Originally Posted by dicktill

There is more to it than just keeping the carburetor clean: there is the issue on all Onan's (propane too) of cleaning the oxide off the commutator. Whether the magic number is 2 hours/month is above my pay grade.

Good point and easy to forget the oxide cleaning aspect of exercising the generator.

I forgot to add that I usually have a few several hours-long runnings each year for air conditioner use or powering electric tools in a remote site.

My vehicle is a 2006 Roadtrek.

[rowiebowie]

Originally Posted by peteco

Good point and easy to forget the oxide cleaning aspect of exercising the generator.

I forgot to add that I usually have a few several hours-long runnings each year for air conditioner use or powering electric tools in a remote site.

My vehicle is a 2006 Roadtrek.

I hope I never have to use the output to run my home fridge due to an extended power outage. But should the need arise, like heaven forbid another hurricane like Harvey that hit just months before I bought my rig, it will be comforting to know I have 2/3 rds of a full tank of gas (at least 20 gals.) which should run the generator for up to a couple of days non-stop.

[CJBill]

I had the same problem and it turned out to be a burnt fuel pump. The one that came out had a burnt brown casing and the one that went had a shinny metal one. It was diagnosed by spraying fuel directly into the carburetor after it had stopped and then it ran.

Bill Dillinger
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