To Exercise or Not Exercise My Onan ... That is the Question

[Sensfan]

For the last ten years, our winterized RT Ranger has been parked in our driveway from November to April. Temperature permitting, I would exercise the Onan generator. Warm weather is coming, however, I am hesitant to exercise the Onan, since, for the first time, I was unable to find any non-ethanol gas to put in the tank prior to winter storage (I have since found non-ethanol gas). My guess is that more than 90% of the gas that the Onan has burned was non-ethanol. So, I do not know if it is better to exercise or not to exercise the Onan. FWIW, the Onan runs great.
Opinions please.

[booster]

Originally Posted by Sensfan

For the last ten years, our winterized RT Ranger has been parked in our driveway from November to April. Temperature permitting, I would exercise the Onan generator. Warm weather is coming, however, I am hesitant to exercise the Onan, since, for the first time, I was unable to find any non-ethanol gas to put in the tank prior to winter storage (I have since found non-ethanol gas). My guess is that more than 90% of the gas that the Onan has burned was non-ethanol. So, I do not know if it is better to exercise or not to exercise the Onan. FWIW, the Onan runs great.
Opinions please.

Did you preserve the gas you have in the tank? The can really minimize issues.


Even fresh ethanol fuel can gel in the carb in less than a month based on what we saw when we had our Onan.


For now, I think I would put a dose of Seafoam in the tank gas at a dosage of probably in between the storage amount and cleanout amount. I think that will let you make it through until spring and might even clean it out a bit.

[Sensfan]

Originally Posted by booster

Did you preserve the gas you have in the tank? The can really minimize issues.


Even fresh ethanol fuel can gel in the carb in less than a month based on what we saw when we had our Onan.
For now, I think I would put a dose of Seafoam in the tank gas at a dosage of probably in between the storage amount and cleanout amount. I think that will let you make it through until spring and might even clean it out a bit.

Thanks Booster. I will add seafoam and take the RT for a run to mix it in with the gas. Very few Canadian stations provide ethanol free gas theses days, which sucks big time.
How frequently did you put seafoam in the tank when you had your onan?

[booster]

Originally Posted by Sensfan

Thanks Booster. I will add seafoam and take the RT for a run to mix it in with the gas. Very few Canadian stations provide ethanol free gas theses days, which sucks big time.
How frequently did you put seafoam in the tank when you had your onan?

In the beginning I would put it in if the van was going to sit for more than a couple of weeks. We always tried to return home with about 3/8 of a tank so less Seafoam needed.


Later on I added a splice in port to the fuel line so I could run the Onan off of that with pure gas. When we got home I would just run about a pint of pure gas into the Onan and it would be good for over the winter.


We have been over 8 years without the Onan and don't miss it a bit. Stinky, noisy, shaky, high maintenance all gone.

[Sensfan]

[QUOTE=booster;152291]. ... We always tried to return home with about 3/8 of a tank so less Seafoam needed.


Good idea. I am however hesitant to do this because of the belief that ethanol in a two-thirds empty tank may, over several consecutive storage months, combine with the large volume of tank air to create more water than would be created than if the tank had been full.

[booster]

[QUOTE=Sensfan;152295]

Originally Posted by booster

. ... We always tried to return home with about 3/8 of a tank so less Seafoam needed.


Good idea. I am however hesitant to do this because of the belief that ethanol in a two-thirds empty tank may, over several consecutive storage months, combine with the large volume of tank air to create more water than would be created than if the tank had been full.

If you sit outside, and especially if you get big temp and humidity swings I would not do it our method as full is best. At that point it either takes a lot of Seafoam or you haul a bunch of cans of pure gas home. We store inside in climate controlled so works for us OK even in Minnesota winters which really can put water in the gas.

[Sensfan]

[QUOTE=booster;152296]

Originally Posted by Sensfan

If you sit outside, and especially if you get big temp and humidity swings I would not do it our method as full is best. At that point it either takes a lot of Seafoam or you haul a bunch of cans of pure gas home. We store inside in climate controlled so works for us OK even in Minnesota winters which really can put water in the gas.

For sure, its not worth the risk. Looks like its finally time to get serious about modifying our electrical system. The majority of our off grid electrical supply feeds our two way Norcold refrigerator. In lieu of planning solar with increased battery storage, I will research the pros/cons of connecting the Norcold directly to a quality portable lithium battery system.

[jjrbus]

If I wanted to use large amounts of Seafoam I would look up the MSDS and find out what chemicals are in it. Then instead of putting oil and alcohol in my tank would buy a can of Naptha. I would prefer a polyether amine product. Which the way I read it is a much better cleaner. Of course I could be wrong

[Sensfan]

Originally Posted by jjrbus

If I wanted to use large amounts of Seafoam I would look up the MSDS and find out what chemicals are in it. Then instead of putting oil and alcohol in my tank would buy a can of Naptha. I would prefer a polyether amine product. Which the way I read it is a much better cleaner. Of course I could be wrong

Thanks. The primary objective of placing any additive in the tank will be to prevent ethanol from affecting the operation of my Onan carburetor, not to clean our Chevy's motor, which runs great. Until now, our Onan has been fed pure gas only, but this is no longer possible, since finding pure gas in Canada has become difficult to impossible, depending on location.
IYO, would napha remove/prevent Onan carburetor glazing?

[jjrbus]

Originally Posted by Sensfan

Thanks. The primary objective of placing any additive in the tank will be to prevent ethanol from affecting the operation of my Onan carburetor, not to clean our Chevy's motor, which runs great. Until now, our Onan has been fed pure gas only, but this is no longer possible, since finding pure gas in Canada has become difficult to impossible, depending on location.
IYO, would napha remove/prevent Onan carburetor glazing?

I don't have an opinion on it Naptha is also known as white gas such as Coleman fuel. I would not use it and prefer to exercise my generator to keep it clean.

[DaveBad]

As Booster previously mentioned. "Splicing" in a line is a good option to get a good gas/seafoam mixture directly into the carb/genny. Here's what I did:

- First I installed a 2-way fuel valve. In position "1" the fuel goes from the vehicles’ fuel tank to the generator as normal. In position "2" the fuel is shut off completely to the generator. In position "3" I have a piece of fuel line that I can drop into a jar of seafom and gas mixture that will now go directly to the carb. I leave the extra fuel line connected but I plug the other end and stow it up in the frame with a tie wrap.
- The valve: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[avanti]

Perhaps the best solution may be to continue this discussion for another month or so, at which point it will become moot. 😊

Seriously, though, although occasional "exercise" of an Onan genset is a good idea, my experience is that the the whole issue is greatly exaggerated, and the "every month" thing that Onan recommends is mostly CYA. Admittedly, though, my experience has been limited to propane units, so...

[Sensfan]

Originally Posted by avanti

Perhaps the best solution may be to continue this discussion for another month or so, at which point it will become moot. 😊
Seriously, though, although occasional "exercise" of an Onan genset is a good idea, my experience is that the the whole issue is greatly exaggerated, and the "every month" thing that Onan recommends is mostly CYA. Admittedly, though, my experience has been limited to propane units, so...

Maybe, maybe not. This Forum is all about the sharing and respecting of opinions. With respect, I disagree with your opinion that "the whole issue is greatly exaggerated", lol.

[booster]

Originally Posted by Sensfan

Maybe, maybe not. This Forum is all about the sharing and respecting of opinions. With respect, I disagree with your opinion that "the whole issue is greatly exaggerated", lol.

I think I will throw out a third choice as, IMO, this is not a binary decision between believing or not believing the Onan recommendations.


First off, I think there are far too many variables in all this to give single solution, even though Onan does give one.


Second is that OEMs commonly want to error to the "safe" side of recommendations, with the possible exception of lithium battery related businesses , in their specs, for warranty and liability reasons.


There are a couple of major variables that cover most of it, I think.


The first is the difference between fuel type and delivery method. Propane generators don't have the ethanol fuel, carb fouling, issues at all so the exercising moves toward the remaining issue of keeping the slip rings clear of oxidation or other corrosion. I think the whole question of if the new EFI inverter models will be less susceptible to the ethanol has not been answered to this point. It is very possible they can handle the ethanol better as do our vehicle engines.



Second is the entire use pattern of the camper, especially during the storage periods most of us have.


Is the vehicle stored in a warm and dry climate, either by location or climate control?


Is it stored in a warm, high humidity, large temp swing, maybe near salt water area?


Is it stored outside in a cold climate where temp swings and thawing can cause major condensation issues.



Someplace in between.



How long is the storage time?


I think most of us know which of the above are better or worse so won't go into that.


My guess is that the Onan spec if based on the very worst case scenario. Parked by gulf in the bayou of Louisiana with ethanol fuel in a gas model or such, pretty bad. Preserve the fuel and exercise often. Stored inside anywhere in a climate controlled area with pure gas and you are probably easily good for a complete winter, I know we were. Same, but with ethanol fuel just treat the gas and made sure it is in the carb by running and good to go based on our experience.


Most will fall somewhere in the middle of all this stuff and should take it all in to account in making a decision, but in general the propane folks will have it much easier to reduce exercising I think, because the fuel related stuff mostly goes away.

[avanti]

Well, as I said, all my experience is with propane, but FWIW, in the 15 years or so that I owned a genset (I no longer do), I diligently ignored the "exercise monthly" stuff and had zero issues (except for one loose ground strap that was certainly not fuel related).

OTOH, I have LOTS of experience with motorcycles and snow blowers. In those cases, I was always careful to run the engine dry before storage by shutting down the fuel supply, thus presumably emptying the carbs. This has always appeared to be effective, even with long-term storage and crappy gas. I wonder if that is a viable option with gas gensets?

[booster]

Originally Posted by avanti

Well, as I said, all my experience is with propane, but FWIW, in the 15 years or so that I owned a genset (I no longer do), I diligently ignored the "exercise monthly" stuff and had zero issues (except for one loose ground strap that was certainly not fuel related).

OTOH, I have LOTS of experience with motorcycles and snow blowers. In those cases, I was always careful to run the engine dry before storage by shutting down the fuel supply, thus presumably emptying the carbs. This has always appeared to be effective, even with long-term storage and crappy gas. I wonder if that is a viable option with gas gensets?

I am a little surprised that all the small engines were OK run to stop as you often need to drain the fuel bowl also because it won't empty fully is high enough to keep the jets a some passages in fuel. So for the Onan idea, I think it might well work but it is possible it won't.


I store all of our small engines with pure gas in them (all we use in them) and full wet with a bit Stabil in the fuel. The exception would be the pressure washer because it can sit for years at a time. That I run dry and it has been fine. I am not sure the Stabil is even needed for 6 months with pure gas, though. Two cycle engines need to be run dry or you wind up with oil sludge in everything.

[DaveBad]

I had problems with my new to me gas generator "surging" and hard starting when i first got it. It took a while to get it to run smoothly. Lots of time laying on the ground, reaching in and around the bumper, trailer hitch and the small generator opening to get the carb out. Running it for 15 minutes a month has kept it running great. Maybe it doesn't need it that often but just pressing a button to start it once a month seems way better than the alternative to me.

[avanti]

Originally Posted by DaveBad

Running it for 15 minutes a month has kept it running great. Maybe it doesn't need it that often but just pressing a button to start it once a month seems way better than the alternative to me.

Running 15 min/month may well be reasonable. But Onan's recommendation is to "run the genset at 50 percent capacity (1400 watts) for two hours every four weeks" which in my opinion is bonkers.

[RTRanger]

It’s your choice to exercise or not. Exercising insures reliability. Every facility I have ever worked with exercises their genset regularly under load, from the small units to very large units, it doesn’t matter what type of fuel is used either.

I exercise mine and it starts with just a couple cranks. Since it is buried up under my Roadtrek, the “cost” of exercising is nothing compared to working on a temperamental generator.

Why would Onan know anything about how to maintain a generator?

[Sensfan]

Originally Posted by RTRanger

It’s your choice to exercise or not. Exercising insures reliability. Every facility I have ever worked with exercises their genset regularly under load, from the small units to very large units, it doesn’t matter what type of fuel is used either.
I exercise mine and it starts with just a couple cranks. Since it is buried up under my Roadtrek, the “cost” of exercising is nothing compared to working on a temperamental generator.
Why would Onan know anything about how to maintain a generator?

RTRanger gets my vote for best thread post, lol.