August 16, 2010
MEMORANDUM
TO:  EPA Docket #
FROM:  Cheryl Caffrey, Mechanical Engineer, ASD, EPA
RE:  Comments on Yamaha Website regarding Yamaha engines and ethanol blend fuels _____________________________________________________________________________________
Issues with ethanol fuels are known by the boating industry and are represented by information found on the Yamaha website www.yamaha-motor.com/outboard/faq/viewfaqanswer.  Examples of questions and answers from the website are listed below.

Question


Why do boats seem to have more issues attributed to E10 fuel than cars?




Answer
 

Cars are having issues but are somewhat more tolerant due to typical usage patterns and differences in their fuel systems. Major differences are: 
:: Modern automotive fuel systems (fuel filler, fuel tank, distribution lines and engine components) are closed or non-vented. Once the fuel is pumped into the tank, there is very little circulation of outside air (containing moisture) into the fuel system. 
:: Boats are operated and often stored in a very wet environment increasing the risk of water directly entering the fuel system. 
:: Boats have vented fuel systems which allow moisture laden air to circulate into the fuel tank as the fuel is drawn out of the tank and as the fuel expands and contracts during heating and cooling cycles of the outside air. 
:: Automotive fuel tanks are typically much smaller than boat fuel tanks and are refilled more frequently. A full tank of fuel in a car or truck, typically 20 ~ 40 gals, may be used and refilled every week or two. Boat fuel tanks, typically 40 ~ 100+ gals per tank, may only be refilled once a month during the boating season and typically may sit unused for many months during the off season. 
:: Some boats use fiberglass fuel tanks. Polyester resins can be dissolved by ethanol.

Question


Wouldn't the cleaning properties of ethanol be good for a fuel system?


Answer
 
 
No, fuel systems that have been used for non-oxygenated gasoline will have varnish depos-its and surface corrosion (rust and aluminum oxides). This includes the tanks and pipes used for fuel storage and transportation. Ethanol will clean varnish as well as surface corrosion from any surface it contacts. Ethanol may dissolve plastic resins used to make some fiberglass tanks. The amount of material cleaned from all of these systems can quickly exceed the filtration capacity of fuel system filters resulting in restricted fuel flow. Ultimately engine perfor-mance is reduced and potentially damage to the engine can occur. 

 





Question


Are Yamaha engines compatible with E10 fuel?

 

Answer
 
 
All current models as well as most engines built since the late 1980's have been designed with fuel system components that are tolerant to fresh fuel containing ethanol up to 10% (E10). Outboard fuel systems can still be affected by: water, dissolved gum, varnish, corrosion particles, and dissolved resins that E10 fuel has cleaned from the distribution system and your boat's fuel tanks.


Question


Can I use fuel with a higher percentage of ethanol, such as E15 or E85?

 
Answer
 
 
No, all of the negative issues discussed in this FAQ section will be increased and may cause major damage to the engine.

 


Question


Does Yamaha make fuel additives to combat problems related to the ethanol in E10 fuel?



Answer
 


Yes. We have two fuel additives: Ring Free PLUS and Fuel Stabilizer & Conditioner PLUS. The "PLUS" includes reformulations for our standard Ring Free and Fuel Stabilizer & Conditioner. 

The Ring Free Plus protects against the corrosive affects of sulfur salts in E10 (10% ethanol-blended fuel) on electronics parts and fittings in the fuel system. It is highly recommended for all electronic fuel injected engines (EFI). The Fuel Stabilizer & Conditioner PLUS helps protect fuel system metals affected by E10, helps to prevent fuel oxidation that results in gums and varnishes and keeps fuel fresh and potent up to year of storage. Fuel Stabilizer & Conditioner PLUS is recommended to be used at every gas fill up, not just for storage.

