As most people know, there is a push to clean up the environment, and there are many things that are being done to do this. The one that is impacting the marine industry the most is arguably the use of ethanol blended fuels. Gasoline – Ethanol Blend and the Marine Industry
  • Gasoline – Ethanol Blend and the Marine Industry

  • 10/02/2017


Gasoline – Ethanol Blend and the Marine Industry


As most people know, there is a push to clean up the environment, and there are many things that are being done to do this. The one that is impacting the marine industry the most is arguably the use of ethanol blended fuels. In the automotive industry ethanol blended fuel is not that big of a deal, but we are in the marine industry. This fuel in boats can be a non-issue or it can cost thousands.


Most of the boating public use their boats once or twice a month, and that is where the problem lies. As it sits in your fuel tank it absorbs the moisture from the air and the condensation from your tank as it warms up and cools off throughout the day. As this water infused fuel goes through your fuel system and engine, it can do a lot of bad things.


If this blended fuel sits for long enough, the ethanol that has absorbed water can actually separate from the rest of the gasoline and settle to the bottom of the fuel tank. The pick-up tube in the fuel tank is installed in to be approximately one inch from the bottom of the tank… where all of the separated ethanol is hanging out.  If that happens, and you try to use your boat, you could be sucking about 98% ethanol and 2% water into your engine that is designed to run on gasoline. Bad things happen.


Image result for ethanol fuel line separation




Here are some of those things.


Fuel tank - A lot of the older boats out there have aluminum fuel tanks and the water absorbed into the ethanol can actually increase the corrosion rate and eat away at the metal eventually causing a leak of fuel into the bilge. What happens when liquid pools up in the bilge? That’s right, the electric bilge pump turns on and now you have a boat bar-b-que. I’m pretty sure those are not as fun as the regular backyard kind.


Image result for boat fire


Some boats actually use the inside of the hull as the bottom and sides of the fuel tank and the ethanol fuel doesn’t play well with that either.  It can actually turn the gel coat and fiberglass into a gel like substance.  The engines of yesterday and today don’t like to run on a gel coat/fiberglass/gasoline mixture, if it even gets through the filters.


Most of the newer boats are using a plastic based fuel tank now and that seems to be working better with the fuels.






Fuel lines – Ethanol in the fuel has actually separated the inner lining from the outer lining in a lot of boats.  This can lead to a lack of fuel getting to your engine causing it to run lean. In the short term, no big deal, but in the long term, poof! Your engine could burn up from this. Thousands of dollars to repairs.


Image result for ethanol fuel line separationImage result for dirty marine ethanol fuel filter


It can also make your fuel lines hard and brittle allowing them to crack or break apart and cause a fuel leak.






Filters – All engines have some sort of fuel filter on them, and a lot of boats have water separating filters as well, and it is a great idea to have them. The problem lies in the fact that once a filter gets water in it, it is generally junk and needs to be replaced. Not a lot of money, but a little bit of hassle and time.


Image result for fuel filter with water in it






Some things you can do to combat the damaging effects of ethanol blended fuels:


  1. Don’t use it.  There are quite a few gas stations that sell non-ethanol gasoline in the Tampa Bay area. I don’t think I have been to a WaWa that didn’t have it. If you are fueling on the water, most of the marinas have a non-ethanol option too. Be warned, buying fuel on the water is around a dollar more per gallon on average.

  2. If you cannot avoid using ethanol blended fuel, add a fuel stabilizer immediately. This will postpone the phase separation but not prevent it. In most cases the ethanol will still absorb moisture, it just won’t separate itself from the fuel.

  3. Make sure that you are getting the regularly scheduled maintenance done on your boats engine. This alone can save you thousands, not only from ethanol but also from other things that could go wrong with your engine from everyday use.


All in all, this is an issue that has gone all the way to Washington, DC, and in fact, is still there to this day. There is a push to increase the maximum percentage of ethanol in our fuel from 10 to 15. Many of the marine manufacturers are saying that this would be detrimental to the industry as the engines will not be as reliable with a higher percentage of ethanol. The National Marine Manufacturers Association is working with the EPA to waive this in the marine industry. In the long run, most likely, that would be the best for the consumer.


I hope this helps answer any questions you might have, and Due Course is here to try and answer any other question you might have on any matter of a nautical sort.


Stay safe on the water!


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