Department of Energy: E15 causes “severe damage” to marine engines

Christopher Gerber (
October 25, 2011
Filed under News

WASHINGTON - The results from two studies conducted by the National Renewable Energy Laboratory on the effects of E15 on marine engines were released on Friday, showing that the gasoline and ethanol blend can cause issues including drivability, materials compatibility, increased emissions, and long-term durability in outboard, stern drive and inboard engines, according to the release.

The High Ethanol Fuel Endurance study tested the effects of E15 and E0 on four-stroke and two-stroke Mercury outboard engines that included the 9.9HP four-stroke, the Verado 300HP Supercharged four-stroke and the 200 EFI two-stroke.

In addition to increase fuel consumption in two of the engines, the study showed that E15 caused damage to two out of three outboards and complete failure in the Verado 300HP engine, as well as "degraded emissions performance outside of engine certification limits," according to the release.

The results of the study reinforced the industry's concerns about proper warning labeling at fueling stations. In September, the NMMA, along with the Engine Products Group, filed a suit challenging the rules regarding gas pump misuse controls for gas pumps containing up to 15 percent Ethanol.

According to the NMMA, the new rules would not do enough to prevent possible damage to marine engines from possible misfueling with E15 fuel, and petitioned to require E10 fuel to also be sold at gas stations.

"Current proposals by the ethanol industry to increase the amount of ethanol in gasoline should seriously concern all boaters and owners of other small engine equipment," said Thom Dammrich, NMMA president. "Although NMMA strongly supports renewable fuels as a means to reduce America’s dependence on foreign sources of oil and improve the environment, there is growing evidence that ethanol is not the answer to America’s energy challenge."

Full versions the studies can be downloaded here: Emissions and Durability Test, Fuel Endurance test


11 Responses to “Department of Energy: E15 causes “severe damage” to marine engines”

  1. peter samuelson on October 25th, 2011 7:45 pm

    already have enough issues with E-10 why would anyone institute this regulation on boaters, When are the lobbyists for ethanol going to use common sense ? We need special fuel for watercraft,they have longer periods of sit time, If E-15 was used no boats would be on the water,no boats sold and the tickle down effect begins to all who serve the boater,


  2. Patrick Gallipoli on October 25th, 2011 7:49 pm

    Thanks for this forum.
    I can't stress enough the "wrong" impact that ethanol has had on our industry. This year alone we pumped 30 fuel tanks at our marina for contaminated and separated fuel as well as our customers having to spend over $15,000.00 in unecessary repairs.

    We have also seen a chemical reaction in carbs with this fuel where a white crystaline residue is left behind after the fuel evaporates which clogs jets and affects the runnability of the engines.

    I recommend that the marine industry be exempt from participating in the ethanol subsidy program, general aviation has found a way around this issue.

    Patrick Gallipoli
    Pro-Performance Marine, Inc.


    r. boise Reply:

    Lets start a class action suite against the UD DEPT of ENERGY on the behalf of consumers who have had to pay for repairs caused by E10!!!! Not only the repairs, what about the safety issues related to the use of E10,engine breakdown putting boaters lives at risk!


  3. JRG on October 25th, 2011 11:28 pm

    From the test informstion: "This result was expected since the carburetor on this engine is factory set for lean operation to ensure emissions compliance. Test protocols did not include carburetor adjustment to account for the increased oxygen present in the E15 fuel."



  4. bill mckinster on October 26th, 2011 7:25 am

    Well once again we have showed that CORN if for food!!!!! a hugh amount food we buy all has corn in it,, and why do we pay more for food; because we put it in fuel, that NOBODY wants except the farmers in the corn belt and coorperate farmers that never seen a cow???? And I am NOT in any way against farmers.. Don't blame them(that is the real farmers who get dirty everyday to feed us) So as food for cattle and all livestock goes up, and food at stores goes up, and we ruin our engines with this alternative fuel,, and we have people in our OWN country hungery; and hungery people all over the world??? why do we spend money on this,, pay farmers to grow more and sell it to CHINA ... WE can't drill our off shore sites; and guess who thinks this is all OK OBAMA we need him and all others who support this mass mes,s OUT and let them leave with a full tank of Corn syrup. Bill


  5. E15 causes “severe damage” to marine engines | Performance Product Technologies Blog on October 26th, 2011 11:01 am

    [...] Read More… [...]

  6. JEFF MCNAMARA on October 28th, 2011 9:36 am

    They needed a study for this? Any one who has worked on marine engines in the last 2 or 3 years could have told them this, and saved the cost of the study.


  7. Dave Seemans on October 28th, 2011 9:48 am

    I agree that ethanol is not the answer to our dependence on imported oil.I suspect the last to realize this wil be the ethanol producers and the EPA.The problems ethanol has caused the boating industry are already known. My small truck fleet gets reduced gas mileage because of the alcohol.Small engine carburators are being damaged by ethanol.Have you seen what it has done to the cost of a box of cereal?In the meantime we must deal with the problem.I am doing what I think will help the problem.I use high octane(93) in my two stroke outboard and use additives to reduce water vapor,carbon and varnish.Keeping engines properly tuned should also help.Evidently newer carburators have better rubber parts and fuel lines.I used to run my two stroke dry when shutting down but I felt that lack of oil could cause problems but drying as much gas out of the engine as possible should help.I see some E-0 gas at some marinas but they are few and far between.
    If the EPA and ethanol producers want us to continue using this fuel I feel they should spend some of their money to come up with ways to prevent damage to our engines.
    If anyone has any ideas on how to protect our engines,my bass fishing buddies and I would like to hear from you.


  8. Paul Moldenhauer on October 31st, 2011 8:56 am

    From Marine Repair Service: We too see numerous cases of plugged and corroded carburetors, rotted fuel lines and damaged tanks because of ethanol. This "junk" absorbs water out of the air as the fuel tank breathes with temperature changes. Ethanol also evaporates easier than regular fuel thus exasperating the problem of air born emissions from just sitting there. Not to mention that the real cost of producing ethanol puts this stuff at probably $7.50 a gallon and is only 80% as energy efficient so you need even more of it to do the same amount of work as a gallon of real fuel.


  9. : NMMA members testify before Congress on E15 on November 3rd, 2011 2:45 pm

    [...] Department of Energy: E15 causes “severe damage” to marine engines [...]

  10. MOK on January 18th, 2012 4:41 pm

    All the above points are well made. In addition, we've seen a dramatic decrease in fuel economy with this low grade dog piss. We're seeing lower fuel economy on 28 foot Gradys with twin 4 strokes than we saw on the same boats with twin V-6 2 strokes in 1999!


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