Onan 2500, loosing power?

[Mean_Jeanne]

Hello all:

So I just read a thread by "Old Pilot" (thanks for posting) and I'm having similar, but not exactly the same, problems with my Onan 2500, in that it's suddenly not providing enough power to run certain functions.

First off, I have a 2007 Roadtrek 170 P, with an Onan 2500 Generator (gas powered). The Onan was completely rebuilt a few years back, and it's been running perfectly since then...starts up fine, powers the microwave, plug-in appliances (toaster) and the CoolCat AC (I boondock with the 170).

I had an isolator problem in the spring and had to run the generator a lot more to charge the house battery, but it worked like a champ and still powered everything. I since rectified the isolator issue (thanks loads for your help "phantomjock"), and everything was still fine with the generator to power the aforementioned functions.

However, the last trip I took, I started the generator (all good) and it powered the microwave fine...although it did "sound" a little bit rougher?! Anyhow, when I tried to use the toaster under generator power (not the same time as microwave), the toaster would not engage (stay plunged down...I tried another toaster, same thing so no the appliance itself). This seemed weird to me, as I thought the microwave would draw as much/more power than the toaster.

I then tried the CoolCat under generator power; the CoolCat ran fine with just the fan engaged, but as soon as I turned on the AC, the generator cut out; I tried the generator/AC again several times...same result every time.

So in summary:

- generator has worked perfectly for 3 years (powered all required functions)
- generator was worked harder than normal for a few weeks, still fine
- generator now will power the microwave, but not AC or plugin appliances

Has anyone had something like this happen to them...have any ideas/suggestions? As a non-mechanical guy, I was thinking that maybe the extra work the Onan performed has caused some sort of problem? Maybe the spark plugs are dirty and therefore it's not producing/putting out the necessary power? Really, I have no clue. lol

Any ideas/suggestions would be greatly appreciated.


M

[booster]

Originally Posted by Mean_Jeanne

Hello all:

So I just read a thread by "Old Pilot" (thanks for posting) and I'm having similar, but not exactly the same, problems with my Onan 2500, in that it's suddenly not providing enough power to run certain functions.

First off, I have a 2007 Roadtrek 170 P, with an Onan 2500 Generator (gas powered). The Onan was completely rebuilt a few years back, and it's been running perfectly since then...starts up fine, powers the microwave, plug-in appliances (toaster) and the CoolCat AC (I boondock with the 170).

I had an isolator problem in the spring and had to run the generator a lot more to charge the house battery, but it worked like a champ and still powered everything. I since rectified the isolator issue (thanks loads for your help "phantomjock"), and everything was still fine with the generator to power the aforementioned functions.

However, the last trip I took, I started the generator (all good) and it powered the microwave fine...although it did "sound" a little bit rougher?! Anyhow, when I tried to use the toaster under generator power (not the same time as microwave), the toaster would not engage (stay plunged down...I tried another toaster, same thing so no the appliance itself). This seemed weird to me, as I thought the microwave would draw as much/more power than the toaster.

I then tried the CoolCat under generator power; the CoolCat ran fine with just the fan engaged, but as soon as I turned on the AC, the generator cut out; I tried the generator/AC again several times...same result every time.

So in summary:

- generator has worked perfectly for 3 years (powered all required functions)
- generator was worked harder than normal for a few weeks, still fine
- generator now will power the microwave, but not AC or plugin appliances

Has anyone had something like this happen to them...have any ideas/suggestions? As a non-mechanical guy, I was thinking that maybe the extra work the Onan performed has caused some sort of problem? Maybe the spark plugs are dirty and therefore it's not producing/putting out the necessary power? Really, I have no clue. lol

Any ideas/suggestions would be greatly appreciated.


M

A bit confused as a 2007 170 should have a gasoline 2800 Onan in it.


With all of the older gas powered Onans, the first thing to look at is the fuel.


Did it sit for more than a couple of weeks with ethanol laced fuel in it?


Even for short periods that can reduce power and create surging under load.


The plugging from ethanol is progressive with each sit time until it starts to have a problem so a bunch of short times can be as bad as one or two long times sitting.

[Mean_Jeanne]

Originally Posted by booster

A bit confused as a 2007 170 should have a gasoline 2800 Onan in it.


With all of the older gas powered Onans, the first thing to look at is the fuel.


Did it sit for more than a couple of weeks with ethanol laced fuel in it?


Even for short periods that can reduce power and create surging under load.


The plugging from ethanol is progressive with each sit time until it starts to have a problem so a bunch of short times can be as bad as one or two long times sitting.

Hello Booster:

Thanks for the response...and good catch with the Onan; you're right, it's at 28K, not 25. So our Roadtrek sits for 2-3 months between trips, and I do put regular in her, so perhaps that is what's going on?! Are you suggesting it would then be the fuel filter for the Onan that is getting plugged?

[booster]

Originally Posted by Mean_Jeanne

Hello Booster:

Thanks for the response...and good catch with the Onan; you're right, it's at 28K, not 25. So our Roadtrek sits for 2-3 months between trips, and I do put regular in her, so perhaps that is what's going on?! Are you suggesting it would then be the fuel filter for the Onan that is getting plugged?

If ethanol gelling in the carb is the issue, which is really possible considering what you stated, the best solution is to treat the gas in the tank with Seafoam to the concentration they suggest. Depending on how full the tank is, it could be a lot of Seafoam.


Then run the generator under load for 20 minutes and let it sit overnight, and then repeat the above multiple times until it runs better. If it doesn't help after 4-5 cycles it may be another issue.


The overnight sit time is important as that is when the Seafoam has time to dissolve the gel in the carb passages so it can flush out during the next run cycle.

[Sensfan]

Originally Posted by booster

If ethanol gelling in the carb is the issue, which is really possible considering what you stated, the best solution is to treat the gas in the tank with Seafoam to the concentration they suggest. Depending on how full the tank is, it could be a lot of Seafoam.
Then run the generator under load for 20 minutes and let it sit overnight, and then repeat the above multiple times until it runs better. If it doesn't help after 4-5 cycles it may be another issue
The overnight sit time is important as that is when the Seafoam has time to dissolve the gel in the carb passages so it can flush out during the next run cycle.

My comment does not apply to this Onan 2800 thread due the age of the chevy RT motor. However, FWIW to owners of newer RTs, I read online that Seafoam is not designed for motors with direct injection. The local Chevrolet dealer indicated that GM started introducing direct injection engines beginning around 2014.

[booster]

Originally Posted by Sensfan

My comment does not apply to this Onan 2800 thread due the age of the chevy RT motor. However, FWIW to owners of newer RTs, I read online that Seafoam is not designed for motors with direct injection. The local Chevrolet dealer indicated that GM started introducing direct injection engines beginning around 2014.

Do you have link or other source for this?

I have never heard that, in fact Seafoam can be used in the aerosol version to clean DIG engine intake valves by spraying it into the intake or a vacuum hose, per a lot of sources I found.

My searches came up empty for manufacturers or anyone recommending not to use it, although many have general warning policies concerning any and all additives.

[Sensfan]

Originally Posted by booster

Do you have link or other source for this?
I have never heard that, in fact Seafoam can be used in the aerosol version to clean DIG engine intake valves by spraying it into the intake or a vacuum hose, per a lot of sources I found.
My searches came up empty for manufacturers or anyone recommending not to use it, although many have general warning policies concerning any and all additives.

Understood. I have previously put seafoam in my 2012 RT gas tank to keep systems clean; no negative effects were observed and my Onan 2800 generator is still running like new after 12 years. However, I have zero mechanical skills or knowledge, and have no comment in regard to the accuracy or inaccuracy of this link. It is included as FYI only.
https://askcarmechanic.com › the-truth-about-seafoam-negative-effects

[booster]

Originally Posted by Sensfan

Understood. I have previously put seafoam in my 2012 RT gas tank to keep systems clean; no negative effects were observed and my Onan 2800 generator is still running like new after 12 years. However, I have zero mechanical skills or knowledge, and have no comment in regard to the accuracy or inaccuracy of this link. It is included as FYI only.
https://askcarmechanic.com › the-truth-about-seafoam-negative-effects

Interesting article on that site, although he doesn't give any references about where he got his information.


He also jumps around a bunch from Seafoam in the oil, to in the gas, to sprayed into the intake so a bit hard to follow which problems are applied to which method.


The points about sludge loosen up and winding up in the pan are true from what I have seen with all oil based cleaners. It can even happen from changing to a high detergent oil in a filthy engines. I would also never drive a vehicle with any of the cleaners that are thin in them, high idle max only and then drain before anything settles. He misleads, IMO, about Seafoam causing sludge as all it is doing is moving existing sludge around in the engine.



He then shifts to plugging injectors with sludge which I don't understand at all because the injectors never see any oil sludge at all and it would have to come from the fuel system. If you had a severely contaminated gas tank with lots of old fuel leftovers (from long sitting gas, especially with ethanol) in the tank it might break them up but the fuel filter should catch that, even the pad type and Seafoam dissolve it. Fuel gelling from ethanol should be dissolved by Seafoam as that is why we use it in the Onans and it works very well for that.


I don't think I would worry about using Seafoam in a DIG engine, unless things change in the future with more information. I would not put it in the oil though unless absolutely needed to address an issue.



The direct injection big killer is gas without enough detergent in it, from many accounts, front carbon buildup on the intake manifold and valves.


Top Tier gas is recommended by many of the OEM vehicle companies to minimize the issue, but around here in Minnesota Top Tier is getting harder to find as many stations have quit having it.


I think anyone who has the carburetor Onans should use Seafoam regularly as it will keep them running well, especially if you get ethanol laced gas and it sits a while. I can't imagine it doing anything bad to rest of the van.

[Sensfan]

Thanks. I’ll be putting some seafoam in my tank this week

[booster]

Originally Posted by Sensfan

Thanks. I’ll be putting some seafoam in my tank this week

Do you ethanol in your gas there? If not, that is a huge benefit for Onan staying running well.

[Sensfan]

Up until about two years ago, it was easy to find non-ethanol gas in Ontario. Our Ranger saw nothing but 91 non-ethanol octane for 10 years. In the last couple of years, however, it has become more and more diffcult to find non-ethanol, especially on trips, to the point where I stopped trying and began putting Stabil in each tank of ethanol-gas. The good news is that I now use 87 octane, which is much less expensive than 91.
IYO, how does stabil match up against seafoam as a preventative tool?

[booster]

Originally Posted by Sensfan

Up until about two years ago, it was easy to find non-ethanol gas in Ontario. Our Ranger saw nothing but 91 non-ethanol octane for 10 years. In the last couple of years, however, it has become more and more diffcult to find non-ethanol, especially on trips, to the point where I stopped trying and began putting Stabil in each tank of ethanol-gas. The good news is that I now use 87 octane, which is much less expensive than 91.
IYO, how does stabil match up against seafoam as a preventative tool?

Bummer on the gas situation for you. We can still get the 91 octane non ethanol fuel here. It is all my 96 Roadmaster gets and also all the small engine stuff.


AFAIK, Stabil will protect OK, but it doesn't clean if you need that, like Seafoam does. For the few years we had the generator we usually overwintered it with Stabil and had no issues.


Our Chevy seems to do fine on the ethanol fuel, except when we got some high elevation mix ethanol fuel that was also a bit low on octane when we were in the Denver area. We quickly found it was losing power due to detonation especially as we got to lower elevations on that tank. We refilled as soon as we could but it was while because of the area we were in with few stations.

[Mean_Jeanne]

This is all great info…thank you both. That said, I’ll have to go with Booster’s suggestion; I have to question the judgement of anyone who cheers for the Senators! Kidding…but not really.

So all of that said B, do you feel that the lack of generator output to power certain appliances (but not others), is the likely cause of my conundrum because of gas? I’ll definitely give it a try as per your instructions (gotta start somewhere)…Just seems strange that microwave works, but others won’t.

Mike

[booster]

Originally Posted by Mean_Jeanne

This is all great info…thank you both. That said, I’ll have to go with Booster’s suggestion; I have to question the judgement of anyone who cheers for the Senators! Kidding…but not really.

So all of that said B, do you feel that the lack of generator output to power certain appliances (but not others), is the likely cause of my conundrum because of gas? I’ll definitely give it a try as per your instructions (gotta start somewhere)…Just seems strange that microwave works, but others won’t.

Mike

Your situation is a bit different than most we hear about that are plugged up carb passages in that you are getting surging of the generator. The surging is the more typical problem.


The fact that you hear it lug down, I think, it is just not putting out enough power for some of the bigger load appliances. The microwave will surge higher and settle at about 90 amps in our 07190. It is rated, IIRC to pull about 900 watts, but ours is a bit more than that. A toaster may be 1500 watts so would need more power if it is that big, best to check. The AC will pull about 110-120 amps on ours so also close to the 1500 of the toaster and AC will pull several times that much on startup.


Low output can be caused by dirty slip rings, faulty governor, or a mixuture issue in the carb, plus a few much less common things. The easiest to do is clean it out with Seafoam to eliminate that possibility and then move on to the others if it doesn't help.


I just noticed that your are in Hawaii, or is the van in the continental U.S.? If you are by the ocean the salt air will corrode the slip rings much faster than normal.

[Sensfan]

Originally Posted by Mean_Jeanne

This is all great info…thank you both. That said, I’ll have to go with Booster’s suggestion;[FONT="Comic Sans MS"][B][B][FONT="Comic Sans MS"][U] I have to question the judgement of anyone who cheers for the Senators! Kidding…but not really.
Mike

You’re entirely welcome Mike. It could have been worse; you could have been taking advice from and thanking a Habs fan, or way, way, way, way worse, a Maple Leafs fan, lol.
Sensfan
Go Sens Go!