Reports show severe E15 damage in marine engines


Last Friday, the U.S. Department of Energy’s Office of Energy Efficiency & Renewable Energy released the results of two studies on the effects of using fuel that is 15 percent ethanol in volume (E15) in marine engines. The studies were conducted on engines provided by two marine engine manufactures — Volvo Penta and Mercury Marine. Both are members of National Marine Manufacturers Association (NMMA).

The reports show significant problems with outboard, stern drive and inboard engines. Results of the reports show severe damage to engine components and an increase in exhaust emissions, reinforcing the recreational boating industry’s concern that E15 is not a suitable fuel for marine engines.

Emissions and durability testing compared E15 fuel and fuel containing zero percent ethanol (E0) and examined exhaust emissions, exhaust gas temperature, torque, power, barometric pressure, air temperature, and fuel flow. Specifically, the report showed degraded emissions performance outside of engine certification limits as well as increased fuel consumption.

In separate testing on engine durability, each tested engine showed deterioration, including two of the three outboard engines, with damages severe enough to prevent them from completing the test cycle. The E0 test engines did not exhibit any fuel related issues.

“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,” NMMA president Thom Dammrich said.

For information, read the full versions of the Emissions and Durability test or the Fuel Endurance test from the Department of Energy.