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Ethanol-infused fuel can cause problems, but don’t expect it to disappear

ethanol plant
As we head into the New Year and an incoming Presidential administration, we thought it was time to circle back with our latest research on the controversy over ethanol in our gasoline. It’s a topic that generates a huge amount of feedback and interest, and we want to publish every credible point of view on the issue.

First, if you think that the new administration has plans to get the alcohol out of your gas, think again. Back in the primary season, every major party candidate for President except one promised Iowa farmers that the ethanol mandate would continue to be part of U.S. law. The lone exception was Senator Ted Cruz of Texas, who did not take the ethanol pledge. “Ethanol is terrific,” said then-candidate Donald Trump last January. With that in mind, ethanol is likely to remain in your fuel for the foreseeable future.

“Ethanol is terrific,” said then-candidate Donald Trump last January. So, ethanol is likely to remain in your fuel for the foreseeable future.

In past articles, we’ve looked at information published by the federal Department of Energy and Department of Transportation, and we interviewed Dr. Andrew Randolph, Technical Director for ECR Engines and former manager of GM’s Advanced Engine Development program.

For this installment, we’ve sought out evidence for the anti-ethanol point of view. What we found is in line with the evidence we presented before. Everyone largely agrees on the facts, but they often disagree on the policy.

The most important thing to know is that ethanol will not hurt your car if it was made after 2001. By that time, all automakers had eliminated ethanol-sensitive materials from production. Cars made in the 1990s will mostly be okay, but the older the car, the greater the possibility that you might have an issue. Classic cars should either be run on non-ethanol fuel, or have ethanol-sensitive parts replaced and the engine dyno-tuned on the fuel you plan to use.

The marine problem

One group of people with a legitimate issue against ethanol is boat owners. Mercury Marine performed extensive tests involving 300 hours of wide-open-throttle testing with outboard engines, comparing performance with E0 and E15 fuel blends and found significant differences. Mercury provided a report to the Department of Energy’s National Renewable Energy Laboratory on the results. The report, “High Ethanol Fuel Endurance: A Study of the Effects of Running Gasoline with 15 percent Ethanol Concentration in Current Production Outboard Four-Stroke Engines and Conventional Two-Stroke Outboard Marine Engines” is freely downloadable right here.

According to Mercury’s report, “Several issues were discovered in this study from an exhaust emissions and an engine durability standpoint as a result of running E15 fuel in outboard marine engines. Run quality concerns were also identified as a result of the lean operation on the carbureted engine.”

Additionally, the report raises concerns about leaving ethanol-mixed fuel in long-term storage due to ethanol’s well-known tendency to absorb water from the air. Because boats are often stored in humid areas near salt water, water absorption can be more pronounced than in other areas.

The specific issues Mercury found in its testing include higher exhaust temperatures in wide-open-throttle testing. This is due to ethanol blends burning leaner than pure gasoline, and over time this can lead to problems with exhaust valves, catalysts, and piston surfaces. Also, the marine engines tested are still built with elastomeric (rubber) components that are sensitive to ethanol degradation.

Finally, the report also expresses concerns about the effect of ethanol on the lubrication system of a two-stroke marine engine. These engines use oil in the fuel to lubricate the bearings and cylinder walls, and ethanol may reduce the oil’s lubrication ability.

Small two-stroke engine testing

The same water absorption issues that affect two-stroke marine engines stored long-term with ethanol-mix fuel also apply to small two-stroke engines used in lawn mowers, chainsaws, and similar tools. Simply put, don’t store your small engines with ethanol fuel in their tanks.

Everyone largely agrees on the facts, but they often disagree on the policy.

However, a study researched by the Oak Ridge National Laboratory found no significant performance and operability changes with these engines using fresh ethanol fuel compared to ethanol-free fuel. Small changes in exhaust and cylinder head temperatures and emissions were noted, along with higher idle speeds. However, according to the report “no obvious materials compatibility issues were noted during the limited duration of this program.” The report did note that multi-cylinder small engines seem to be more susceptible to differences in air-fuel mixture between cylinders, and this might cause issues.

You can download the entire report and read it for yourself at this link.

Motorcycle issues with ethanol

Motorcycle owners should also be cognizant of ethanol damage. Motorcycle manufacturers continued to use fuel system parts susceptible to ethanol damage after automakers changed over. Further, many more older motorcycles are still on the road, since motorcycles typically see less mileage and far less bad weather than cars do.

Ethanol’s tendency to create higher cylinder head and exhaust temperatures are also a bigger issue with air-cooled and two-stroke motorcycles than in automobiles, so many of the wear tendencies observed in boat and small garden engines also apply to bikes.

Automotive testing

The same report from Oak Ridge also covered testing on several 1999, 2001, and 2004 model year vehicles that were determined to have the greatest likelihood of sensitivity to ethanol. In the course of testing, the research team tested each vehicle on E0, E10, E15, and E20 blends.

Several issues were discovered in this study […] as a result of running E15 fuel

Apart from a predictable reduction in fuel economy as ethanol concentrations increased, the report states, “no operability or drivability issues were identified when any of the ethanol blends were used during the limited time of the project. Each vehicle accumulated at least 100 miles on each ethanol blend, and at least 200 miles on gasoline (E0 fuel).”

The fuel economy reduction when running a 20 percent ethanol mix (E20) was 7.7 percent compared to E0 fuel. None of the cars actuated a malfunction indicator light due to the ethanol. None had issues with clogged fuel filters, cold starting at 50 degrees, or any “conspicuous degradation” of fuel system components.

What does it all mean?

This is all pretty dry research, and the reports themselves are quite detailed. What it all means to you is simple – and it comes down to a few easy-to-follow recommendations:

  • Use ethanol-free E0 fuel in your boat or motorcycle and you won’t have any problems.
  • Don’t store ethanol-mixed fuel in your small engines. Empty them and clear the carburetors after every use, or use E0 fuel.
  • If your car was made after 2001, don’t worry. If it’s older than 1990, either update the fuel system or run E0 ethanol-free premium gas. If your car was made in the 90s, it’s probably OK, but check to see if it’s having any degradation to its rubber components.

So, while there are legitimate issues with ethanol in classic cars, inboard and outboard boat engines, motorcycles and small garden engines, those issues are easy to avoid with a little care.

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Jeff Zurschmeide
Jeff Zurschmeide is a freelance writer from Portland, Oregon. Jeff covers new cars, motor sports, and technical topics for a…
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