Ethanol fuel blend and boat motors

What problems can arise from using ethanol fuel blend in a boat motor?

By now almost everyone is aware that today's gasoline contains an ethanol.  Most gas retailers sale a blend of 10% ethanol and 90% gasoline referred to as E10.  The argument of whether this is beneficial remains irrelevant at this time because the Federal Government mandates its use.  What is relevant to boat owners are the effects of ethanol on marine motors. To understand these effects it is important to understand how "overtime" ethanol reacts in gasoline.

Ethanol fuel is basically a grain alcohol made from corn, sugar and other grains.  Ethanol is hygroscopic, which means it absorb water.  Also, ethanol acts as a solvent which can break down resins in rubber and fiberglass.  This solvency can clean out accumulated gunk, varnish and rust.  Then add to this the fact that when ethanol combines with water it can become corrosive.  Can you picture the sludge produced here?

As ethanol-gasoline fuel ages the ethanol begins to separate forming two distinct layers.  The ethanol settles on the bottom of the gas tank along with any absorbed water and sludge matter.  Once the gas tank's fuel pickup begins delivering water/ethanol/sludge mix to the motor; fuel filters clog, carburetor jets plug and the problems begin.

The boat owners who have experienced problems from ethanol notice their motors are hard to start, once started the motor begins to sputter and may stall.  Some motors have the tendency to lack power in the mid throttle ranges as if not firing on all cylinders.  Many owners will attempt to adjust the motor's carburetor or other linkage setting, farther aggravating the problems.

The two major contributors to the ethanol fuel issue are the presence of water in the gas tank and the age of the gasoline.  With changes in air temperature the potential for condensation in a partially filled gas tank is high and many boats are only used sparingly or seasonally which often allows the fuel time to age.

By understanding these points, boat owners can take precautions.  All new boat motors sold in the United States are designed to operate on gasoline containing no more than 10% ethanol. Never use fuel containing more than 10% ethanol.  Also, it is most important to follow the engine manufacturer's recommendations on the use of fuels and read your owner's manual.

If your boat does not have a 10 micro fuel/water separating filter, install one between the tank and motor.  Change the filter every 50 hours.  Buy fuel from a station that sells a high volume of gas (the gas should be fresh).  Buy a name brand fuel and from the same source when possible.  Use a FUEL STABILIZER!!  A stabilizer like STA-BIL 360 Marine will slow the ethanol-gasoline separation while reducing water absorption into the gas.  Add the manufacturer's recommended amount of stabilizer when fueling up.  Avoid using gasoline that is more than 90 days old and after lengthy periods of boat inactivity check for the presence of water in the gas tank (if possible).  Lastly, avoid operating the motor when fuel levels are very near empty.

fuel water separator

Understanding the characteristics of ethanol-gasoline blend and applying the appropriate preventive measures should help to keep your boat motor relatively free of ethanol fuel related problems.

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