Abstract

Ethanol blended fuels have become increasingly prevalent in the on-road transportation sector due to the benefits they provide in energy security, sustainability and reduced environmental impact. However, ethanol usage has led to material compatibility concerns causing corrosion and degradation in materials that are commonly used in engines and fuel storage/delivery systems. The on-road transportation sector continues to study and develop alternatives to minimize potential material challenges. Although, marine vehicles represent a smaller segment of the transportation sector, they represent many vehicles, particularly in the United States. Concerns related to the use of ethanol blended fuels in the marine environment have been expressed by many individuals and groups. Unfortunately, relatively little work has gone into the study of gasoline mixed with approximately 10% ethanol usage and potential material incompatibilities in marine engines. The objective of this article is to provide some factual answers to these concerns. In order to understand the extent of material incompatibilities, a literature survey of published material compatibility data and marine engine manufacturer recommendations was conducted. Next field samples of marine fuels were gathered to estimate the extent of ethanol usage in marine gasoline. Finally, samples of new and in-use marine components were exposed to either gasoline mixed with approximately 10% ethanol or gasoline with 0% ethanol for 1,960 hours to determine whether gasoline mixed with approximately 10% ethanol presented degradation beyond that seen with gasoline (gasoline with 0% ethanol) alone. This work has shown that many marine engine manufacturers have used ethanol compatible materials in current products and that exposure of older marine engine components to gasoline mixed with approximately 10% ethanol by did not reveal any significant degradation. Finally, marine fuel samples gathered in 2013, reveal that most marine gasoline sold in the Unites States does not contain significant levels of ethanol.