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Understanding and Countering the Effects of Ethanol

Posted on 22 Oct 2013 in Powersports, Snowmobile | 5 comments

We have all heard the horror stories about ethanol in gasoline destroying small engines and powersports engines, including snowmobiles.  Most of these stories are true and ethanol really can be harmful, but with the right knowledge and prevention, we can continue to enjoy the sport we love without worrying about costly damages to our machines.  In this post, we’ll try to understand ethanol a little better and how that knowledge can help us run our engines more safely.

Why Ethanol is Bad

There are a few different reasons why ethanol is not good for our snowmobiles, but the worst offender is its potential for Phase Separation.  What the heck is phase separation, you ask?  Ethanol has a very low tolerance for absorbing water.  When enough water is introduced to the gas tank (which is not much at all), the water forms droplets at the bottom of the tank because it is more dense.  It will also pull ethanol with it and out of the gas mixture, which will lower the octane value.  In pure gasoline, much more water is allowed to disperse and mix in.  So phase separation is when water collects at the bottom of your tank because it cannot be dispersed throughout the gas.

Ethanol can also be attributed to the increasing difficulty of cold starts in engines.  When ethanol is introduced, the fuel’s Enthalpy of Vaporization is increased.  Basically, what this means is that the colder the temperature, the more the ethanol will stay in a liquid form.  For combustion to occur, the fuel must be sprayed as a vapor to mix with the air.  The liquid fuel will not combust and, therefore, your engine will not start.

Because ethanol does not burn as cleanly as pure gasoline does, it tends to leave behind debris in the forms of gum and a “varnish” in the engine and carburetor.  These build-ups can lead to the most expensive effects of ethanol.  With excessive build-up, your engine can fail.  While carbon does eventually build with the use of pure gasoline, the use of ethanol can greatly speed up the process.

Ethanol is also a cause for loss of horsepower in your engine.  This is because Ethanol stores about 1/3 less energy than pure gasoline.  The makeup of ethanol reduces the surface area for oxygen to mix with the fuel for combustion.  If you increase the mixture, you will gain more power, but your fuel economy will greatly suffer.

What To Do

The best thing that you can do to avoid the problems with ethanol gas is to avoid buying ethanol gas in the first place.  While this may sound obvious, it is harder to do than it sounds.  More and more states are requiring gas to be mixed with ethanol, but there are still stations out there that carry pure or “Non Oxy” gasoline.  An easy way to find if there is a station around you is to check out  The price per gallon is usually quite a bit higher, but it could end up saving you more money in the long run.

Because one of these gas stations is not always going to be available when you’re going down the trail, there are ways to deal with using ethanol.  One of these things is to add an enzyme stabilizer like Star Tron.  The enzymes in the treatment will help prevent phase separation by dispersing the water throughout the mixture instead of forming in clusters at the bottom.  This will allow for easier starting and it will also help clean the existing gum and varnish out of your engine.  The treatment should be added right away so water does not have a chance to separate from the fuel.

If you have to store gas, you should add the enzyme treatment right away.  You should also try to store it in a cool dry space so the ethanol cannot draw the moisture out of the air.  Phase separation could occur in your ethanol gas as soon as seven days since purchasing.  Once your gas has gone bad, it really should not be used even if you use an additive.  The fuel mixture just will not be able to be brought back to a safe ratio for optimal running.

Using a snowmobile oil that has detergents in it will also help keep the inside workings of your engine clean.  In the past, choosing a snowmobile oil wasn’t that crucial, but now, it can really prolong the life of your machine.

Most ethanol blends are rated to be 10% ethanol, but the percentages can fluctuate.  If you are worried about the levels of ethanol in the gas that you use, there is an easy way to test the levels yourself.  What you need is a 100ml test tube, water and the gas you want to test.  Mark the tube at the 10ml line and fill the tube with water up to that mark.  Then, fill the rest of the 90 ml with the gas and cover with a stopper or you could use your thumb and shake it up.  You are creating phase separation by doing this.  If the separation of the water and fuel goes up, then you have more than 10% ethanol.  For example, if it is at the 15ml line, the ethanol percentage will be about 15%.  To be safe, you should try to avoid any gasoline that has an ethanol percentage higher than 10%.  To watch a video of the detailed process, click here.

Hopefully with this knowledge and these tips, you will be able to avoid the problems that come with ethanol being used in our gas and be able to prolong the life of your machine.


Ryan is one of the lucky ones who gets to combine their passion with work. He has enjoyed powersports his whole life and now gets to write about it. Ryan has been around the industry since High School and continues to enjoy learning and sharing about powersports with others in his role at DK.


  1. Steve Rock / October 22nd, 2013 20:49

    This is horse-poo. The way to deal with this problem is to vote out of office every mo-fo who thought this boondoggle was a good idea. The way to fix this problem is AT THE PUMP. Either these enzymes get added there, or Ethanol gets removed from the mix – period. In addition to two wheel and tracked power toys, I fly airplanes, and Ethanol has ruined the chance of ever using mo-gas in them. Don’t capitulate. I mean thanks for the advice, but it should *always* be prefaced with this: GET RID OF THEM – VOTE THEM OUT – SEND THEM ON DOWN THE ROAD.

    • Ryan / October 23rd, 2013 11:42

      Hi Steve, Thanks for your input. These are just some tips to deal with what we are given so we can continue to enjoy the powersports that we love.

  2. Al / August 7th, 2015 20:10

    Purchased an older boat. The gas in it was ‘varnished’. We are unable to remove the tank. How else could we clean the gas or remove the remaining that is left.

    • Ryan / August 10th, 2015 8:00

      Hey Al. If your boat has a primer ball you can disconnect the line from the motor and then remove the connector to have an open line. You can then squeeze the primer until no more gas comes out. Another way would be to snake a siphon into the gas tank if there isn’t a screen blocking it. Hope this helps.

  3. Jared / October 3rd, 2015 10:48

    Don’t know if I am on the right board but I must ask. Can I use this in my car? It is a 2010 Chevy Malibu v-4 engine. I have moved to Florida and everything has ethanol in it except for the few places that sell “marine rec fuel” in which I don’t want to put into my car.


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