On a recent camping trip my friend's Honda generator broke down. When he took it in for repairs the mechanic immediately dove into the carburetor and pulled out a rock-hard rubber diaphram. According to the mechanic he's been seeing this problem in literally hundreds of small engines since ethanol has been added to gas. Ethanol will cause rubber to stiffen up and become brittle, thereby screwing up your carburetor. As a chemist, I know this is a true effect. Everything I make at work has to undergo compatibility tests with also sorts of materials (rubber, neoprene, Tygon tubing, Vitex, etc...). I have to avoid using ethanol in anything that will be pumped by our smaller pumps as they contain rubber gaskets and the such.

If you have a generator or other small engine you may want to pick up a few spare diaphrams for it and learn how to replace them yourselves, especially if the generator is for emergency use. Repair shops aren't open under such circumstances. ETS member kmat was run ragged keeping his neighbors' generators running after hurricane Ike, though in most of those cases it was stuff like clogged fuel filters. As all these generators sit until next time the rubber will turn to rock and then all these people will be screwed unless they have the parts on hand.

-Blast

I think the idea was that the gas would be so much cheaper that it would have offset the mileage difference. Of course, that never happened. I'm waiting for switchgrass gas.
Ethanol was also harder on older cars when it first came out because of the gasket material they used to use. Currect gaskets in autos usually aren't really rubber so there is no wear penalty in your car anymore. I'm surprised that the small engine industry never followed suit.
I know a few people who have never even unboxed their generators and don't have any gas to run them, but feel prepared.

In my area, ethanol is only added to gasoline from October through March (or thereabouts). So stocking up on fuel for a generator in the summer would be preferable.

You can't make gasoline from switchgrass. You can make ethanol with it. Modern gasoline combustion engines can't run on pure ethanol, not without some serious modifications anyway. Switchgrass isn't a panacea but it's a helluva lot smarter than the current model using corn.

As for the running on corn oil, I think you may be thinking of the original diesel engine which was actually run on coal oil and can now run on vegetable oil. I have 2 Mercedes Benz diesels that have been modified to run on used vegetable oil. Works like a charm. And of course there's also bio-diesel which is simply refined vegetable oil, another great alternative to both gasoline as well as petroleum diesel.

John E

Currently we can't even do that. Ethanol made from cellulose is still years away.

Getting back to the thread, one could buy aviation gas for their generator. This gas is high octane and is not allowed to contain ethanol. It is a bit pricier though. Maybe a mix of av-gas and regular gas would help by cutting down the percentage of ethanol.

It might be possible to extract the ethanol by washing the gasoline with water then using a separatory funnel followed by some sort of drying agent to remove the water from the gas. The question with this technique is what else would be removed from the gasoline (surfactants, light-end molecules, etc...)?

-Blast

Blast, is it even worth the trouble to try and wash out the ethanol? Seems like it would be easier to just keep those spare parts as you described earlier.

John E

Can't you buy gas without ethanol in your area? You still can here and I'm in the middle of corn country.

And there is the difference between an engineer and a chemist.

It probably depends on how easy it is to acquire and replace the parts. I would think a big-name generator would have spare parts available while with some no-name Chinese gen this could be an issue.

My friend's generator was acting funky for hours before it quit. This suggests one would have some warning and could make the repairs without being under pressure/in the dark/whatever.

-Blast

Thanks for the heads up- my dad stores his with a full tank, so I'm afraid to think about out the crud that might be in there with this in mind.

Vermont, we run something like 10% ethanol. *shudders* Nothing is made for that.

The percentage of ethanol in Florida is 10%. There is supposed to be an exemption for marinas because the fiberglass tanks in boats will disintegrate with E10.

Around town i don't notice a lot difference in milage, but highway is a different story. The one thing that is odd is one of the cars has a slight shake at idle on ethanol, the uneven shake like it has a cam in it. Thought it needed a tune but i have talked to a few other people with similar problems.

Have not noticed any problems with the small engines.....yet.