America’s drive to reduce its dependency on foreign oil has led to a rapid expansion of ethanol-blended fuels. Today, ethanol can be found in nearly every gallon of the nation’s gasoline and is presently being utilized in all engine types, including marine engines.
E10 (10% ethanol, 90% gasoline) is interchangeable with gasoline. In fact, the fuel specification for unleaded contains ethanol. E10 should be used as fuel for marine engines and watercrafts, not E15 or any other higher ethanol blend. Until fuel blends containing more than 10% ethanol have been tested and approved for use in marine engines, watercraft and boat owners should not use these higher fuel blends.
To download a brochure on Ethanol and Marine Use, click here.
Engine Performance:
Ethanol provides high octane for exceptional engine performance and reduced emissions. Need proof? Just ask the National Boat Racing Association (NBRA), they are using E10 exclusively for all their races. Using E10 should not present any major problems if recommended best management practices are utilized.
There are over 12 million recreational boats in the United States, some of which are considered vintage watercraft. Regardless of make and model, most watercrafts can operate on E10. For instance, Honda, Kawasaki, Mercury Marine, OMC (Johnson/Evinrude), Pleasurecraft, Tigershark (Artco), Tracker and Yamaha allow the use of ethanol fuels in their products. As an example, Mercury Marine has indicated that their outboard products, produced after 1979, should not have problems operating on ethanol.
Ultimately, your watercraft operator’s manual should be consulted. If you do not have access to the owner’s manual, contact the engine manufacturer or authorized dealer. Remember, a wealth of information on your marine equipment is available to you on the internet as well.
2011 NBRA Ethanol Racing Series
Facts about E10 & Winterization:
•Adding ethanol does not shorten the shelf life or stability of motor fuel, nor does it affect the combustibility of the fuel.
•Winterization techniques from the fuel storage perspective are typically identical for gasoline and E10 fuels with some additional warning as to water or condensation contamination for ethanol blended fuels. Having your watercraft prepared for storage by an authorized facility is always the preferred method.
•Additional fuel storage recommendations, specific to your geographic location, may be available from the local, authorized marine servicing dealer.
Proper storage preparation is essential for keeping your marine motor trouble free and running smoothly. Seasonal changes in the ambient temperature can cause the freezing water or condensation to build-up inside the engine and fuel tank. One key point for methods of winterization: Always follow the procedures and recommendations outlined in the Owner’s Manual.
Most manufacturers recommend one of two winterization storage methods for marine fuel systems:
1) Dry Storage Method: Drain all the fuel from the fuel tank and operate the equipment until it stops due to lack of fuel. *Never start or run your marine engine without water circulating through the cooling water intake in the gear case.
2) Wet Storage Method: Treat the fuel with a fuel stabilizer to extend the fuel’s storage life. Once treated, fill the equipment fuel tank to 90% full. After adding a fuel stabilizer, run the engine to be sure that the treated fuel has replaced the untreated fuel. *A partially full tank is not recommended because the air space above the fuel allows air movement that can ultimately cause fuel deterioration.
Fuel Deterioration:
Ethanol and gasoline are completely miscible. If excessive moisture is introduced to the ethanol/gasoline fuel mixture, the ethanol and water can phase separate (fall out of suspension) from the fuel blend. This would result in a mixture of ethanol and water in the bottom of the fuel tank, separated from the gasoline. Aside from the fact that the engine would not operate on this ethanol/water blend, it can also cause corrosion of the various metals with which it comes in contact. Such occurrences are rare, especially if proper maintenance and storage recommendations are followed.
Gasoline and E10 fuel blends can oxidize and deteriorate in storage, leading to gummy deposits in the fuel system. Old gasoline can cause hard starting due to “weathering of the fuel,” meaning a loss of the easier vaporizing components of the fuel from evaporation. Very warm storage temperatures accelerate this type of fuel deterioration. If the gasoline in your fuel tank and carburetor deteriorates during storage, you may need to have the carburetor and other fuel system components serviced or replaced.
As a regular maintenance item and prior to a boating trip, check for water contamination of the fuel tank. If any water is found, remove all of it and dry the tank completely before re-fueling. Also, since E10 can absorb moisture, it is important to have a tight fitting cap on both your equipment fuel tank and any gasoline storage containers. Any phase separated material should be handled as hazardous waste and properly disposed.
Frequently Asked Questions:
1. Are marine engines compatible with ethanol fuels?
Nearly all manufacturers have designed their marine engines to successfully operate on ethanol blended fuels up to 10%.
2. Can I use ethanol in my motorboat?
Yes. Ethanol is the oxygenate of choice in some water-recreation areas because of its clean air and clean water benefits.
3. What about my two-stroke powered engines? Will the ethanol affect the lubricity of my gasoline-oil mixture?
The National Boat Racing Association (NBRA) uses two-stroke marine motors that exclusively run on E10. To date, tests have shown no problems using E10 in two-stroke equipment when the manufacturer’s recommendations are followed.
4. Can I use E10 in an outboard motor? What about an inboard motor?
Fuels containing up to 10% ethanol are considered acceptable by most marine engine manufacturers & will not void the engine warranty. Some offer special guidance on E10’s use, such as specific storage instructions. Always confirm with your owner’s manual from the manufacturer if you are unsure.
5. Can I use E15 in my marine engines?
No. This fuel is specifically for use in light duty vehicles model year 2001 and newer, and all flex fuel vehicles.
6. I see other ethanol blends such as E20 and E85. Can I use these products in my marine engines?
No. These fuels are for use in flex-fuel vehicles (FFVs) only. These automobiles are specifically designed to be able to operate on ethanol blended fuels ranging from unleaded gasoline to E85 (85% ethanol, 15% gasoline), and all mid-level blends in-between.
7. Is ethanol better for the environment?
Yes. Ethanol is biodegradable, and helps reduce emissions. Using ethanol-blended fuels not only keeps the water clean, but also the air.
8. What are some common material compatibility warning signs if I have used the wrong fuel?
If rubber components are suspected to be incompatible, check with the manufacturer for advice or frequently inspect these fuel system components for signs of swelling or deterioration. Replace them if problems are noted.
Since the 1980’s, many rubber and elastomer engine components were designed to be both gasoline and E10 compatible. The U.S. Coast Guard has provided guidance for watercraft owners seeking a replacement for the fuel hose applications. Retrofit model, J1527USCG. Type A1, is the highest performance hose with the best resistance to ethanol blends.
For more technical information, please refer to the following: RFA Update for Boat Owners, Ethanol and Marine Use: Frequently Asked Questions or E10 and Winterization.
