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Old 07-04-2019, 05:52 AM   #1
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Default Generator exercise

Here's a link to a discussion on this topic...

https://www.rv.net/forum/index.cfm/f...d/26755059.cfm

Apparently, there's some people on this forum who disagree.....that's very unfortunate and gives the impression that some of us shouldn't be following the manufacturer's advice.....I don't agree and think this is not helpful..my two cents.....

Read the conversations above on this link....and make your own decisions......
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Old 07-04-2019, 07:05 AM   #2
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Most of us learned the hard way that the manufacture's recommendations are correct and we are in no mood and wallets are in no shape to learn it twice.

Drain the carburetor before even a few weeks storage.
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Old 07-04-2019, 11:55 AM   #3
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Originally Posted by Roadtrek Adventuous RS1 View Post
Here's a link to a discussion on this topic...…

https://www.rv.net/forum/index.cfm/f...d/26755059.cfm

Apparently, there's some people on this forum who disagree.....that's very unfortunate and gives the impression that some of us shouldn't be following the manufacturer's advice.....I don't agree and think this is not helpful..my two cents.....

Read the conversations above on this link....and make your own decisions......
As usual you have taken a lot of what was said here out of context and misrepresented it in now a new discussion without showing the original statements.

Here is what I actually said in the a recent discussion.


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Onan is doing a KYA on some of this stuff, not surprising at all.

When you are talking commutator corrosion, I can tell you with absolute certainty that it is the conditions the genny is stored in that make by far the biggest issue. We had an Onan in our 07 until a couple of years ago and it sat for a year before we sold it after removing it, plus it would almost always only get run maybe once over winters. BUT, and this is a big but, it was stored over winters in our very air tight and always above freezing (mostly 50*+) garage. When it sat for a year, it was in an engine bag and in out crawlspace in the house.

When I pulled it out to sell it, the buyer wanted to see it run and check the output of it to spec. Smart guy to want that, but it meant me setting it up to do that. It started up fine with new gas (old was drained and run dry before storage) and immediately on warmup it put out OVER spec at nearly 3K watts. This generator was a decade old and had something like 30 hours on it.

If this generator had been in an outside stored van here in Minnesota, it would not have done well, I am very certain.

The absolute worst place to put the generator is under the van as the heating and cooling of the metals lags the air temp by a whole lot. You will repeatedly be getting moist air onto a generator that is below the air dewpoint of the air and condensing. Warm sunny days will melt snow right by the edge of the van and under it from the the warmer air and it drifts right under where the generator is still cold from overnight or colder weather.

I have a similar issue in the garage only in the summer as the garage is very will insulated and can run 25* or more less than outdoor temps in the summer. If I open the doors on humid day I get condensation on all the stuff in the garage that has high thermal mass like the vehicles, steel workbench and welding table, lathe and mill. That was the only time I worried about the generator, but those doors aren't opened often or very long so it was infrequent enough not to matter enough to show up. If bench didn't rust, I knew I was OK.
This is a personally tested experience and plainly stated that it was the conditions that made it possible. It is also plainly stated that IMO Onan is doing a CYA based on worst case conditions, which I do think is true. It is also plainly stated that if the genny were in worse conditions, my experience would likely have not been the same.

The premise and the statements were that the Onan requirements don't always apply BASED ON THE CONDITIONS.

Now, you tell us just how much data you have to back up that the Onan recommendations need to be followed in all cases or there will be a failure. Your generator failed while, I assume, following all the recommendations. Does that mean that the Onan recommendations cause failures? No, it doesn't, IMO, but it is one more data point that you have provided to say not following the Onan recommendations will cause problems.

Provide some data, that will be the "helpful" information. Taking shots with no actual reference to statements, just vague misrepresentations doesn't qualify.
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Old 07-04-2019, 12:27 PM   #4
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Originally Posted by Roadtrek Adventuous RS1 View Post
Here's a link to a discussion on this topic...

https://www.rv.net/forum/index.cfm/f...d/26755059.cfm

Apparently, there's some people on this forum who disagree.....that's very unfortunate and gives the impression that some of us shouldn't be following the manufacturer's advice.....I don't agree and think this is not helpful..my two cents.....

Read the conversations above on this link....and make your own decisions......
"Apparently, there's some people on this forum who disagree.....that's very unfortunate"

Not for me, I appreciate other ways to think besides yours or LOUD onan's. There are lots of forum members here that correct my thinking at times. After given some thought 12 plus years ago I deliberately decided on 30-40 minutes about every 35 days. It has worked out well. Now if I had run it 3 times longer, would it be happier today or running at all? I might be using a quiet Honda by now.

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Old 07-04-2019, 01:03 PM   #5
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Most of us learned the hard way that the manufacture's recommendations are correct and we are in no mood and wallets are in no shape to learn it twice.

Drain the carburetor before even a few weeks storage.

I think most everyone would agree with this part the maintenance for gas units, especially the newer ones with the tiny fuel passages. I would add that adding seafoam to the gas when storing also seems to work as well as draining and running dry, maybe better if there is already some plugging.


Propane units don't have the carburetor issues, so then the interval really gets to be how long can they sit before the slip rings corrode too much and drop or eliminate the output of power. Onan doesn't differentiate on the corrosion and gas fouling issues, and it is very possible that there would be different maximum no use times. But as I mentioned, the corrosion thing appears to be so very heavily influenced by conditions, it makes it virtually impossible to put a single timeframe on the exercise frequency needed to prevent damage. That would be why Onan recommendations are what they are, at the very far safe end of the scale by making the interval the same as the carburetor ones, as they don't know what the conditions will be. To blanket say that that interval is needed, or not needed all the time, is pretty much impossible IMO.


For those that store their vans in areas where it is easy to run the generator regularly, it is not a big deal to do fairly often, but we very, very, often get questions about offsite or non accessible storage of vans with Onan generators and IMO the questioners deserve a better answer than being told they absolutely, positively, need to follow the Onan schedule or the generator will fail. A thorough explanation of the differences between propane and gas and how conditions can make a huge difference is what those folks need see so they can assess their risk potential and mitigate it as needed.
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Old 07-04-2019, 02:09 PM   #6
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Most of us learned the hard way that the manufacture's recommendations are correct and we are in no mood and wallets are in no shape to learn it twice.
Been there... done that... got the t-shirt. Won't do it again!
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Old 07-04-2019, 02:23 PM   #7
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I think most everyone would agree with this part the maintenance for gas units, especially the newer ones with the tiny fuel passages. I would add that adding seafoam to the gas when storing also seems to work as well as draining and running dry, maybe better if there is already some plugging.


Propane units don't have the carburetor issues, so then the interval really gets to be how long can they sit before the slip rings corrode too much and drop or eliminate the output of power. Onan doesn't differentiate on the corrosion and gas fouling issues, and it is very possible that there would be different maximum no use times.
Having now spent upwards of $2k on generator repairs and maintenance at Cummins/Onan (on two different generators) and having used those service appointments to chat at length with some Onan techs, I've gleaned that there are several issues addressed by exercising the generator. First, of course, in a gasoline, carbureted generator is keeping the fuel system from varnishing up. That's a particularly critical issue on the 2800 because the jet orifices are so small. Onan makes a great income from selling replacement carbs and fuel pumps. The second is to keep the internals in the generator free from corrosion. And the last is to make sure that the generator is run long enough at operating temperature to evaporate any accumulated moisture/acids off out of the oil.

Unfortunately, we as consumers typically don't do the tear-downs of broken generators to see what condition they're in. The techs do, and I'm now a believer in that Onan and the techs know what they're talking about. And if you don't believe the factory and their recommendations, it's only money, right?

So, I now dutifully run both my Onans, a propane 2.8kw in the Airstream Interstate, and the 7.5kw gas generator in the Born Free 32RQ the requisite number of exercise hours monthly; the exception being when I store the Born Free off-site for the winter. It (as well as the 8.1L V8 ) gets run with Seafoam (recommended by the Onan tech) in the proper mixture in the gas tank. The 7.5kw is a considerably larger engine, of course, and doesn't seem to be as prone to the varnish issues as the 2800, but I still do my due-diligence in exercising it.

They tell stories of servicing generators with THOUSANDS of hours on them that, other than routine service, have had no repairs. My '95 Coachmen was 20 years old, had 26k miles on it when I bought it and the generator had 26 hours on it. That one cost me, in total, $1500 to get it running properly. It appears to be a case of "use it or lose it" when it comes to Onan generators; and that appears to be particularly true of the various iterations of the 2800.
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Old 07-04-2019, 03:55 PM   #8
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First, of course, in a gasoline, carbureted generator is keeping the fuel system from varnishing up. That's a particularly critical issue on the 2800 because the jet orifices are so small. Onan makes a great income from selling replacement carbs and fuel pumps.
This only applies to gasoline units. I have no experience with petrol Onans, so I will make no strong statements here. However, unless they are somehow different from every other small gas engine I have owned (a large number), simply running the unit dry before storage should be just as effective, and far more sane. This procedure has NEVER failed me across many, many engines.

If I had a gas genset, I would add a motorcycle-style petcock to the fuel line and use it every time I shut down the engine for any length of time.
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The second is to keep the internals in the generator free from corrosion.
As I said above, I believe that this is an issue, and agree with Booster that the magnitude of the issue is environment-dependent. What I DON'T believe is that this issue ever requires running monthly for two hours. This is simply bonkers. There is nothing exotic about these slip rings, and they will typically rapidly develop a very light layer of surface oxidation. This layer will be abraded away after a few seconds of running. If you leave it unrun for many months, you MIGHT have an issue (although, depending on the environment, the surface rust tends to seal the metal, greatly slowing additional rusting. This is why unpainted steel buildings don't rust away). But, in any normal environment, we are talking about many months before irreversible harm is done. "Exercise" your unit three or four times a year, and this will never be an issue. I have no doubt that the CYA text (which is many years old) was motivated by units which sat idle for years on end (which I suspect is common).
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And the last is to make sure that the generator is run long enough at operating temperature to evaporate any accumulated moisture/acids off out of the oil.
This I totally agree with. As I said above, when you DO start it up, make sure it gets good and hot before you turn it off again or you will do more harm than good. This is true of any ICE. Even here, though, two hours under load is certainly an extremely conservative number that I bet was pulled out of the air by some tech writer long ago with no engineering backing. What could possibly happen during the second hour of such a run that didn't already happen during the first one?

I say again, my opinions here are backed by fourteen years of experience over two propane-powered Onans (which always ran flawlessly and never received the absurd monthly 2-hour "exercise"), as well as a great many other similar devices. Any evidence-based responses that contradict these opinions are heartily welcome. However, the continued constant repetition of "appeal to authority" arguments would be worthless and tiresome. "It says so in the manual" is indeed a piece of evidence, but it is far from proof, especially when the statement lacks face validity, as this one certainly does.
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Old 07-04-2019, 04:17 PM   #9
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Even here, though, two hours under load is certainly an extremely conservative number that I bet was pulled out of the air by some tech writer long ago with no engineering backing. What could possibly happen during the second hour of such a run that didn't already happen during the first one?

I say again, my opinions here are backed by fourteen years of experience over two propane-powered Onans (which always ran flawlessly and never received the absurd monthly 2-hour "exercise"), as well as a great many other similar devices. Any evidence-based responses that contradict these opinions are heartily welcome. However, the continued constant repetition of "appeal to authority" arguments would be worthless and tiresome. "It says so in the manual" is indeed a piece of evidence, but it is far from proof, especially when the statement lacks face validity, as this one certainly does.
While I agree that the two-run-hour/month recommendation appears to be a one-size-fits-all solution, and at least the carburetor/fuel pump varnish issue is limited to the gasoline models; what I don't understand is the vitriolic backlash that some here appear to have about it.

All I can do is share MY experience which is that exercising the generator per the recommendation keeps it running trouble-free. If you find the recommendations of the manufacturer to be untenable, then just don't do it. It's really simple.

I find that the same argument applies about engine oil change interval arguments that seem to rage across every website that deals with ICEs. If you think the manufacturer's recommendation is too short, don't change it as often. If you think it's too long, change it more frequently.

What's the big deal?
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Old 07-04-2019, 04:27 PM   #10
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While I agree that the two-run-hour/month recommendation appears to be a one-size-fits-all solution, and at least the carburetor/fuel pump varnish issue is limited to the gasoline models; what I don't understand is the vitriolic backlash that some here appear to have about it.
The only reason I participate in groups such as this is to gather and occasionally contribute valuable and accurate information on various topics. When I have evidence that suggests that information is inaccurate, I try to help correct it. This is true whether the information comes from other members or from an OEM.

The only thing I get "vitriolic" about is when somebody repeats over and over again that "a Fortune 500 manufacturer said it, so it has to be true." As I have repeatedly said, I warmly welcome other points of view, so long as they are evidence-based--certainly including yours.
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Old 07-04-2019, 04:43 PM   #11
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When I have evidence that suggests that information is inaccurate, I try to help correct it. This is true whether the information comes from other members or from an OEM.
I certainly appreciate all the good information and opinions that we get from folks here, and they can be useful in evaluating specific recommendations we see. That said, there has to be a "gold standard" for "accurate" information somewhere.

The "gold standard" information on Onan generators remains the Onan manuals and by extention, the experience of the Onan trained techs who service the products daily. My experience as well as that of others has shown that in this case the manufacturer's recommendations keep the product generally trouble-free and operational, regardless of our opinions about it. There's really no down-side to following the recommendations, so I'm still just not sure what the controversy is.

But that's just me... and we'll leave the issue here.
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Old 07-04-2019, 04:45 PM   #12
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While I agree that the two-run-hour/month recommendation appears to be a one-size-fits-all solution, and at least the carburetor/fuel pump varnish issue is limited to the gasoline models; what I don't understand is the vitriolic backlash that some here appear to have about it.

All I can do is share MY experience which is that exercising the generator per the recommendation keeps it running trouble-free. If you find the recommendations of the manufacturer to be untenable, then just don't do it. It's really simple.

I find that the same argument applies about engine oil change interval arguments that seem to rage across every website that deals with ICEs. If you think the manufacturer's recommendation is too short, don't change it as often. If you think it's too long, change it more frequently.

What's the big deal?

I would not call it vitriol, just a rebuttal to a derogatory remark about having our opinion is "unfortunate" and "not helpful" in the first post of this thread, which totally ignored what had actually been said. Nobody told anybody, that I know of, that they should ignore the Onan requirement, just that there plenty of information around that indicated the requirement was likely overly conservative and that might want to be considered, and that propane and gas versions would likely also have vastly different actual requirements.



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Apparently, there's some people on this forum who disagree.....that's very unfortunate and gives the impression that some of us shouldn't be following the manufacturer's advice.....I don't agree and think this is not helpful.

I totally agree with you that everyone should decide for themselves on stuff like this, and that is why the information was discussed in the first place, to give everyone that choice. As mentioned, what do you tell those that need to store a van in an inaccessible place for the winter or over the very short Onan requirement when we know it is done by many folks, all the time, successfully? To state that giving that information and opinion is "unfortunate" and "not helpful" while give exactly no information or data other than the Onan statement, is to me more "not helpful".
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Old 07-04-2019, 04:53 PM   #13
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"My experience as well as that of others has shown that in this case the manufacturer's recommendations keep the product generally trouble-free and operational, regardless of our opinions about it."

Huh? That is an opinion, or else prove it. I read and read 13 years ago and decided on not going with the 2 hours with 12+ years of success. Others have posted their experience religiously running 2 hours, only to have the onan fail and fail multiple times. You can't recall posts like that?

"There's really no down-side to following the recommendations, so I'm still just not sure what the controversy is."

You can't think of any downside?

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Old 07-04-2019, 05:14 PM   #14
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A thing to make perfectly clear to all.


There is really no question that the Onan recommendation will keep the generator healthy. I doubt anyone said or believes otherwise.



The question is if that recommendation is way more than needed, depending on the many, many, other factors involved and lots of experiences of users.


There is a big difference between the two questons.
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Old 07-04-2019, 05:35 PM   #15
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"There is really no question that the Onan recommendation will keep the generator healthy. I doubt anyone said or believes otherwise."

Not exactly, not necessarily booster. Running my onan 3-4 times More, Longer keeps the generator healthy? I think that it wears a lot faster, may have failed by now with so many many more hours.

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Old 07-04-2019, 05:55 PM   #16
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Maybe Onan's recommendation is for people like me. When I initially got my rv I read about the 2 hrs. per month recommendation. While I intended to adhere to it, I've not run mine that long or that often in my 20 months of ownership.

If they'd suggested one hour every few months, heck, I might not even have used it between trips. Time just gets away from me sometimes.

I was extremely lucky when Hurricane Harvey hit and koocked out power for several days. My home emergency generator fired right up and ran like a champ (after I drained 2 year old gasoline out of it filled it with fresh).
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Old 07-04-2019, 08:34 PM   #17
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If these problems exist primarily with the gas genny, why don't more people have the propane powered one? Just curious.
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Old 07-04-2019, 09:01 PM   #18
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If these problems exist primarily with the gas genny, why don't more people have the propane powered one? Just curious.
LP generators aren't as convenient when it comes to their fuel needs.

Gasoline generators feed from the main fuel tank, and you've got 30 gallons +/- of fuel to use at roughly a quart of gasoline an hour. Basically, you have a nearly unlimited fuel supply because you top off regularly when driving.

Most of the Class B vans have a single propane tank that has a capacity of between a five and eight gallons, and an LP generator uses roughly a half-gallon an hour giving you a mere ten to twelve hour run time for the generator alone... not counting the use of other propane appliances, and propane isn't as easy to find nor fill.
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Old 07-04-2019, 09:10 PM   #19
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"There is really no question that the Onan recommendation will keep the generator healthy. I doubt anyone said or believes otherwise."

Not exactly, not necessarily booster. Running my onan 3-4 times More, Longer keeps the generator healthy? I think that it wears a lot faster, may have failed by now with so many many more hours.

Bud
Bud, I have no interest in arguing with you, but your supposition is in direct opposition to the position the Onan techs I've met have taken. They've told me that essentially you just can't wear one out. Failures occur primarily because of fuel system issues that manifest from non-use. I recognize that's a generalization I can't back up with factual data. I'm just passing along the recommendation of the guys who DO deal with them.

And again, if they recommend the two-hour/month exercise regimen to prevent fuel system and whatever else fails, what's the big deal about running it for two hours/month? It's no more labor-intensive than running it an hour a month, and an extra quart of gas or half-gallon of LP gas certainly isn't going to break anyone up in business. And most of us have the oil changed every year anyway because the 24 hours/year is about all the time they get anyway. I use mine what I consider to be quite a lot, and I still doubt I put 50 hours a year on them.
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Old 07-04-2019, 09:12 PM   #20
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LP generators aren't as convenient when it comes to their fuel needs.

Gasoline generators feed from the main fuel tank, and you've got 30 gallons +/- of fuel to use at roughly a quart of gasoline an hour. Basically, you have a nearly unlimited fuel supply because you top off regularly when driving.

Most of the Class B vans have a single propane tank that has a capacity of between a five and eight gallons, and an LP generator uses roughly a half-gallon an hour giving you a mere ten to twelve hour run time for the generator alone... not counting the use of other propane appliances, and propane isn't as easy to find nor fill.
Agree with hepcat, but there is only one downside of gasoline not plural, I think. Surging when the jets become varnished, thus seafoam. No big deal, just needs to be deal with appropriately and prevented.

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