This is taken directly from the website www.lookbeforeyoupump.com
You spend too much money on that beautiful Mercruiser to have it damaged by the wrong fuel so take heed.
Most gasoline now contains 10 percent ethanol (E10). But, you may see higher ethanol blended gas available for sale – such as 15, 30, 50 or 85 percent ethanol gas – at a gasoline filling station.
These higher ethanol blends may even be cheaper than E10, and you might be tempted to buy the higher ethanol content gasoline because of its lower cost. But, price is no longer the way to choose your gasoline safely. You have to choose the right fuel for the right application.
Higher ethanol blends (above 10% ethanol) are not meant for outdoor power equipment such as mowers, garden tractors, chain saws, boats, snow throwers, trimmers, UTVs, power washers, blowers, chippers, grinders, generators, jaws of life, concrete saws and other compact construction equipment, as well as small engine applications such as water pumps and irrigation systems.
Are higher ethanol blends really that harmful to outdoor power equipment?
Yes. You might be tempted to use a higher ethanol blended fuel since it may be less expensive. However, greater than 10 percent ethanol in outdoor power equipment can corrode metals and rubber and cause engines to break down more quickly. Most outdoor power equipment was not built, designed or warranted to run on fuel greater than E10, and using higher ethanol blends can damage or destroy it. In fact, using any fuel that contains more than 10 percent ethanol is illegal to use in outdoor power equipment.
Also, the higher the ethanol blend, the lower the fuel economy. Ethanol contains 33 percent less energy per gallon than gasoline, so engines fueled with higher ethanol blended gas will attain fewer miles per gallon than those running on conventional gasoline (E10). This means you must fill your gas tank more frequently when using higher ethanol blended fuel.
- See more at: http://opei.org/ethanolwarning/consumers/#sthash.iAIREDYX.dpuf
What Should I Do When Getting Gas?
Understand which fuel is appropriate for your equipment. Read the equipment's operating manual for specific fuelling requirements.
Look before you pump. Check the etanol and ensure it is the right fuel for your engine product.
Select the correct gasoline for that specific product to protect your equipment investment.