REPORT abnormal test results and problems with ethanol fuels.
Ethanol alcohol fuels in marine engines - Warnings and necessary precautions.
Fuel Testers provides information and gas alcohol test kits to manage E10 ethanol blend renewable fuels.
Ethanol alcohol, a renewable reformulated fuel, supports the farming industry and decreases U.S. dependence on foreign fuels.

BRP Evinrude Ethanol Bulletin March 29th, 2007:
Contact a certfied Evinrude Johnson station or Email Fuel-Testers for a PDF copy.

Marine Outboard Driveability Effects of 10 and 20 % Ethanol on Engines: Marine Manufacturer Fuel Recommendations, 2003
Study by Orbital Engine Company February 2003. View online or Email Fuel-Testers for a PDF copy.

Marine Manufacturer Fuel Recommendations: View Summary.
Herman & Associates, 2003. View online at or Email Fuel-Testers for a PDF copy.

View more Bulletins and Warnings issued for Boaters...

Ethanol alcohol blend fuels, made from corn & grains, can damage engines.
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WARNING: E10 gasoline is not safe for most boat engines due to ethanol's ability to attract and absorb water into fuel...

An Alcohol Fuel Test Kit will give you
the data you need
to keep engines safe
with E10 gasoline.
Portable, reusable Alcohol Fuel Test Kits protect marine engines by checking the ethanol/alcohol content of fuel, now used at most public gas pumps.

E10 Information for Marine & Boat Owners
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The sad reality is that e10 ethanol-blended fuels are not safe for most marine engines.

What's most shocking is that despite years of studies, research, and reports that reveal the dangers and inconvenience of alcohol fuel blends, most marine motor owners are still unaware of the risks and necessary precautions when using E10 fuel, which is now being sold widespread at public gas pumps.

It is an unnecessary and costly hardship that consumers seem to only become knowledgeable on E-10 ethanol blend fuels after the damage has been done to their engines.


Alcohol has been used as both a fuel and/or gas additive throughout the century.  Extensive research studies have been published for decades on the challenges, risks and damage alcohol can cause to engines.  The recent surge in alcohol-blend fuels is primarily due to the requirements of the "Renewable Fuel Standards" 2004 -onward and "The Clean Air Act of 2006".  But, consumers have only very recently begun to understand the chemical properties and potential damage from E-10 fuel.

Many manufacturer fuel recommendations for conventional engines (check your owner's manual) and engine warranties forbid against all ethanol and gasahol fuel. As recent as 2003, Mercury, Bombardier and other major marine/boat manufacturers advised against E10 and all ethanol blends of gas.
Only FFV's (Flex Fuel Auto Vehicles), specifically designed for E85 gas are resistant to high gas alcohol levels. Caution: No marine engines exist that can run safely on E85.

Risks are greatest for boat engines primarily due to ethanol's ability to attract and absorb water (diluted fuel, phase separation, water contamination, rusting of parts, etc.)
ethanol's solvent and cleansing properties (wears down parts, dissolves and breakdowns or dries out parts, releases accumulation of dirt, rust and sediment, etc.)

To add further insult to the government's poorly chosen decision to switch conventional petroleum gasoline to a 10% alcohol blend, many areas still do not inform consumers with E10 sticker labeling and some areas no longer offer a choice for pure (non-alcohol) gasoline.

So why do we ignore the truth and permit laws to promote, require and increase distribution of E-10 alcohol fuel?

The answer is far more complex than the effects and risks of alcohol fuels.  Fuel and petroleum control all aspects of our economy and culture - including financial (stocks, bonds, GNP and prices of all consumer products), environmental, foreign relations, auto-makers (engine designs and manufacturing) and the most basic necessities of everyday life - including cost of food and manufacturing of almost all consumer goods. 

E-10 gas has strained the relationship of American's love for fuel.
Boating and marine enthusiasts have the least chance of surviving the hurt and damage.

By the time ethanol became the EPA's solution to replace MTBE for oxygenating gas in late 1990's-2000, the decision-makers already knew alcohol would present many risks, expenses, and inconveniences to the public.  Since marine engines account for only about 5 % of fuel consumed, the U.S. government's response to the concerns of the marine community has sadly been disinterest,  Although increased warnings have been issued to boaters, by the EPA and marine manufacturers and organizations since the mid to late 1990's, most boat owners seem to be unaware of this information.

Why Does E10 Gas Present the Greatest Challenge to Marine Engines?

Ethanol and alcohol has many chemical properties which make it incompatible with marine engine use.

Alcohol is a solvent, degreaser, that is miscible and hygroscopic (absorbs large quantities of water). Basic science reveals water and oil do not mix well together - marine engines live in the water and are used most often during humid summer months.  It's the mixture of petroleum (oil) with alcohol that's the primary problem, not ethanol alcohol alone.

Understanding basic scientific principles support the incompatibility of mixing ethanol with petroleum for marine gasoline use.

Marine engines pose a greater risk than automobiles because marine engine owners:

-  replace fuel in their boat tanks less often than in automobiles,
-  leave fuel in the tank for extended periods of non-use,
-  have fuel systems that are often vented (not sealed),
-  use engines that are more prone to rust from water exposure,
-  use marine engines less frequently and expect them to last longer than their automobiles,
-  engine's manufactured more than 10 years ago often contain parts not resistant to alcohol,
-  often use fuel additives and treatment products that are alcohol-based (especially rust inhibitors and water removers) which are incompatible with E-10 fuel, and
-  are often unaware that fuel contains alcohol, because most state laws still do not require pump labeling when ethanol is added to gas.

Since it's impossible to avoid contact with water in a marine engine, and unreasonable to expect boat engine owners to replace well-maintained older engines, careful monitoring and fuel precautions are now necessary.

E10 Fuel is NOT Safe For Marine Engines

Copyright. Article written by G. Alexander, Owner FUeL-TESTERS a division of MLR Solutions.

Read Marine & Boating Problems with Ethanol:

Read Warnings, News and Bulletins for Boaters:

READ about Using Fuel Additives & Gas Treatments with E10:

Additional Suggested Actions for Boat Owners Concerned about Ethanol Fuels:

- Know the specific fuel laws and fuel composition in your state and be aware that private marine gas stations are not required to follow the same laws that pertain to public gas stations.

- Purchase premium, high octane fuel labeled 91 or above, (which legally excludes ethanol in some states), and also offers an extra level of safety in the event fuel contaminates with water, which will cause the octane rating to drop about 3 points.

- Support marine manufacturers and boating organiziations who are actively involved in an effort to obtain legal exemption of ethanol in marine gas.

Many Warnings & Bulletins Have Been Issued By Marine, Auto and Other Manufacturers

For copies of important bulletins and warnings issued by the EPA and engine manufacturers contact Fuel-Testers
(Include your engine type, model, year and name & contact information with request).

Short-Term Solutions

Until boat owners are given better choices, the best short-term solution is to avoid the use of any fuels or additives that contain alcohol/ethanol.

Ethanol should be used primarily in E85 gasoline, not conventional petroleum fuels (E10). This will decrease our dependency on foreign oil imports and pollution, and will protect consumers from unnecessary damage when their conventional motor is not compatible with ethanol.

We recommend testing fuel for alcohol content and percentage.  - Visit  for more information on  Alcohol Fuel Test Kits.  There are many other simple precautions and actions marine engine owners can take to avoid most of the problems they will encounter with E-10.

Article and information contained on this website can not be reproduced or copied without permission from the author and owner of Fuel-Testers and


About Ethanol - Site Contents: History, E10 gas, disadvantages, benefits, precautions, renewable gasoline, marine, automobile...
Report abnormal test results and/or problems with ethanol fuels.
Necessary Marine Precautions When Using E10 Fuel

To prevent damage to your boat engine it is now necessary to follow some simple and effective precautions, which include:

- Test gas for alcohol to assure it is below the legal limit of 10%,

- Replace the gas in the tank every 2-3 weeks and purchase gas from busy name-brand gas stations,

- Check gas in tank for early signs of water contamination and phase separation,

- Install a water-separator filter if not already present in your engine,

- Avoid all fuel additives that are alcohol or ethanol-based,  Example: Evinrude 2+4 Fuel conditioner contains 95% alcohol.

- Keep engine well-lubricated and tuned to protect engine parts from the damaging effects of alcohol,

- Check your owners manual for fuel types recommended - If you have an older engine which probably does not permit alcohol fuel use, formally contact to the manufacturer for fuel recommendations.

- Check your engine warranty for details and consequences when ethanol alcohol is the cause for engine damage. Most conventional engine warranties clearly state that repairs are not reimbursable when fuel used is greater than 10%. (Often boat owners unknowingly cause this danger by adding additives to tank that contain alcohol.

- Become aware of the symptoms and effects of "bad gas" which are caused by alcohol levels that are too high. This includes stalling, hesitation when under WOT, smoke released from exhaust, clogged fuel filters and carburetors, the malfunction of or damage to VRO pump or pistons, disintegration of engine parts (especially rubber and plastic), drying-out of parts (hoses), and more.

- Article and information contained on this website can not be reproduced or copied without permission from the author and owner of Fuel-Testers

Read All Precautions at: ethanol_engine_precautions.html
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