Generator and Ethanol

[chuckbear]

Has anyone found issues in older gas generators using the current ethanol gas. Ours is a 1999 Onan 5500. I'm wondering if I should have any concerns or look for any telltale signs? Chuck

[pjstough]

I would say that if you have been using ethanol blended gasoline, and the generator is working fine, you should be ok, however, if you havent been using ethanol blended gasoline, and plan on start using ethanol blended gasoline, you could run into plugged fuel filters, as the ethanol in the gasoline will clean your fuel system.

 

In the two motorhomes we have owned we didnt know if previous owners had used ethanol blended gasoline or not, but we went ahead and started using ethanol blended gasoline in both, and have had no problems with the generators on either motorhome.

[chuckbear]

Thanks Paul, what year is yours? Chuck

[pjstough]

Our first motorhome was a 1988 model we bought in 2005 with an Onan 4000 watt generator that we used for four years. Our current motorhome is a 2005 with the 5500 watt generator.

[redcrzr]

I just purchased a new Honda generator and was advised by the tech. that demonstrated the unit to use a fuel additive. I was planning on using Sea Foam because of advice from this forum and he said that he uses it in all of his small engines.

I've never heard of the "cleaning" abilities of ethanol, but I have heard of the issues with excess condensation and water.

Todd E.

[Mark and Dale Bruss]

Ethanol is fine for engines that run often, like our cars. For lightly used devices, like many of our generators, ethanol combines with water in the fuel and makes a gummy substance that can plug ports in the generator. Ethanol normally get blamed for eating seals, the gumming is much worse.

 

Running the generator on a regular basis is important.

[Kirk W]

Ethanol has been in gasoline in this country since the 1990 Clean Air Act so it was in use before your generator was built and most likely that was considered in it's design. We bought our fulltime coach in May of 1998 and burned fuel from the main gasoline tank the entire 14 years that we owned it with no problems at all. Because your generator uses a carburetor it is important that it be run at least monthly to prevent the evaporation of the fuel from causing a buildup of varnish in critical areas. I also found it to be very helpful to always use a fuel stabilizer in the fuel tank when planning to sit for an extended period and the Onan tech folks suggest that as Ford who built your chassis. In addition, Onan recommends that their generators be operated under load for at leas 30 continuous minutes each month, both to flush the fuel system and also to dry out any moisture that may have built up inside of the generator.

 

It is very difficult to prove that something was prevented by use of any item or product but while some may scoff, I have long believed that an ounce of prevention was worth many pounds of correction!

 

EDIT: The generator that you have is the exact same as the one we had, but one year newer.

[chuckbear]

Thanks everyone. The generator is getting plenty of use right now. Almost daily. It sits on the lot here at our marina and there is no adequate plug in. So while I'm working on it, I need the AC and the genny is running for at least a few hours every day. For the last few days, it has been harder to start and will surge at times. Today it was even harder to start but seems to be running fine. That was the reason for considering the ethanol, since 40 years in the marine industry has made me well aware of what it can do to older engines. I plan on giving the gas tank a treatment of Seafoam just in case. That has worked well for me with marine engines. Chuck

[Kirk W]

For the last few days, it has been harder to start and will surge at times. Today it was even harder to start but seems to be running fine.

If you have access to a fitting in the fuel line, that set has the fuel pump on the engine so you can easily break the fuel line and use a hose to supply fuel from a can that has a good mix of gasoline and carb cleaner. I used to do that at the first sign of surging because that usually means it is getting gummed up. I would supply it that way for 2 - 3 hours, then reconnect the normal fuel line.

[chuckbear]

Thanks Kirk, yesterday it was pretty stubborn about starting. Once it did start and had a couple of minutes to warm up, no surging. I will see how it acts today. Chuck

[Sehc]

My onan surged. It was a spark plug.

[Kirk W]

If you don't have one, most of the Onan manuals can be found online, thanks to Google's search tool.