Ethanol in Gasoline- What You Need to Know (by Jim Tucker)
Published on Saturday, January 9, 2010 in Guest Columns, News & Updates, Snowmobile Tech
Tags: ,

Picture this: You pull up on your snowmobile to the gasoline pump, lift the handle and are going to fill up. Before you do you notice the sign on the gas pump that says, “contains 10% ethanol.” So, you top-off the sled, drive away and wonder to yourself – what is ethanol? What will it do to my snowmobile? Will I need to add gas line antifreeze? Do I need any octane boosters? Oh well, nothing has happened before, so why should I have to worry?

All those questions are valid concerns and need to be addressed by facts, research and past history. With the high cost of new sleds, all the component parts of a sled, and aftermarket high performance bolt-ons, we as snowmobilers demand answers to what it is that we put in our sleds. Granted, we don’t have much choice in the fuel we use, as there are no buttons at the pump saying choose solar, nuclear or electric, but they may be working on it! Ha, Ha!

So why do we have any additives in gasoline at all? Why not use just straight gas and be done with it? The Clean Air Act of 1970 brought forth by the EPA and Congress started the quest for cleaner air emitted from internal combustion engines and other sources. This Act stated that we should reduce harmful pollutants spewed into the atmosphere by the internal combustion process including carbon monoxide, benzene and other dangerous toxins out there.

Okay, so cleaner air was the goal, but how do we get there? Well, the brain trust thought that MTBE, a fuel oxygenator, was going to solve the problem. After several years of lousy engine performance and polluted groundwater that idea went the way of the Dodo bird. Fast forward to today when ethanol enters the picture and is thought to be the Holy Grail to reduce pollutants.

Look Before You Pump logo

So what is ethanol? Ethanol has been in use since 1978 and is basically ethyl alcohol, same as in booze, and distilled mainly from corn. Ethanol is hydrophobic, which means that it absorbs water, and as such, has to be added at the terminal and not the refinery. This, plus the fact that it is distilled from organic food products, increases our final cost on gasoline purchases. Ethanol is also a degreaser, or solvent, which will actually clean internal engine surfaces.

Interestingly, while ethanol reduces benzene and carbon monoxide levels it has about a 3% lower BTU or heat output than regular gasoline. The by-product of this distillation process will act to reduce the overall octane rating of gasoline, which in turn reduces performance somewhat in a modern snowmobile engine.

Another interesting fact about ethanol is that it is an oxygenate, which means that due to the added oxygen molecules found in alcohol, it tends to lean the mixture out somewhat. Studies have also been done showing that the reduction in octane rating and the nature of the ethanol gas mixture results in higher exhaust temperatures and therefore higher engine component temperatures.

Ok, so the sled runs hotter and leaner. Now what? With regard to two-strokes, heat is a major concern in longevity, performance and reliability of the engine. Most of the modern snowmobile fuel delivery systems are of an open-loop design, which means that there is no exhaust feedback circuit to tell the ECU or electronic control unit to richen the mixture for lower octane or hotter temps. Only timing in these systems can be retarded or advanced due to the gas component of the combustion process. This poses several problems to address by the engine manufacturers, and their answer is to make the overall fuel map richer in all areas of the power band to compensate for this.

There have been postings recently on the Internet about some folks saying that their machines have blown up possibly due to the 10% ethanol in gasoline that they used. Perhaps the problem lies in the water that may be in the tank and not the ethanol that is present. Combine this with a good number of riders out there that have high performance goodies installed. With leaner and hotter mixtures, this pushes the engine closer to the edge. Combine that with very cold temps, which naturally lean out the mixture, and the result can be a recipe for disaster.

Arctic Cat C-Tech2 600 engine

Mind you, proper engine tuning, a solid knowledge of two-stroke engine dynamics, and a good set of exhaust gas temperature gauges, will go a long way in keeping an engine happy. Gasoline itself is only one component of the overall picture. Folks have also said that the ethanol eats seals up, ruins gaskets and corrodes aluminum inside an engine. Modern day seal technology and metallurgy has solved this problem and anything made after 1980 will be ok in that regard.

So now what about the “contains 10% ethanol” sign? With a ten-gallon tank on your sled, you can possibly have up to one gallon of alcohol in there. Remember that it can contain up to 10% Ethanol. The actual amount may be 1, 2, 3, 5 or any percent up to 10. Only the refiner will really know this fact and this can only serve to keep consumers guessing as to what is really in there.

Another question to ask is, do I use gas line antifreeze? Since the gasoline itself has alcohol in it already and already absorbs water the answer still would be yes, but in way smaller doses than recommended on the container. A good rule of thumb would be to add about two or three ounces or shot glasses of gas line antifreeze. You need this protection because if you let the sled sit out overnight there may be condensation in the tank and when you go to start the sled the next morning that water has frozen in the fuel line or carburetor. More than that amount and you might dilute the gas even more and make the overall mixture leaner. Remember to add only isopropyl alcohol and never methanol antifreeze to a two-stroke.

How about four-strokes? How does the lean condition and added heat affect them? Not much, as four-strokes can withstand and run at much higher temperatures anyways. They still need some gas line antifreeze though, as mentioned above.

So, now I hope you have a better understanding of that sign, “contains 10% ethanol.”

Part two has some updates and corrections to this story:

(Read Part Two of the Story)

Sources: and

« | »

Return to full list of entries