Seven Tips for Living With Ethanol
 Check and drain water separators regularly. Enough water will cause phase separation, even within the filter.
 Inspect rubber parts, primer bulbs and fuel hoses — even ethanol-resistant hoses marked J-1527 — for swelling, softness or cracking. With electricity and fuel turned off and a bucket to catch spills, check fuel hose innards too.
 Monitor fuel tanks, vents, fills and gauge sender gaskets for water leaks, and check bilges for gasoline.
 Advice is mixed on fuel storage levels. Full tanks don’t breathe much as temperatures change, so a full tank of ethanol is less likely to absorb moisture from humid air, but E10 shouldn’t sit unused.
 Stabilizers seem to mitigate many problems. Use recognized brands labeled for E10, like those from StarTron (startron.com), ValvTect (valvtect.com) and Sta-Bil (goldeagle.com), particularly if fuel won’t be used completely in a week or two.
 Don’t switch frequently between E10 and unblended gas.
 Learn your engines’ normal noises and proclivities, and see a trusted mechanic at the first sign of change.
4.4gph: The fuel burn at 3,000 rpm with ethanol running through a 150 hp Mercury Verado on a Boston Whaler 180 Dauntless. Straight gas ran at 3.9 gph. In our test it was a hard-to-hold 3,000 rpm. The tach wanted to constantly fall with ethanol and constantly rise with unblended fuel. Mercury engineers say ethanol’s decreased energy will show most noticeably as decreased torque — exactly what we saw at 3,000 rpm.
1 mile: Extra distance achieved per gallon of E10 compared with unblended fuel when driving my 2008 GMC Sierra without a trailer. Mileage was nearly identical when towing an 8,100-pound load. Automobiles have far fewer problems with ethanol than boat engines do because fuel systems are closed to outside air and because entire tanks of fuel are burned and filled more regularly. Still, mileage was supposed to decrease by about 2 percent with the ethanol. Weather differences could have been a factor, as could the wintertime blend of E10 I tested versus the summertime blend of gasoline, or even the way the truck’s sensors were responding. All of this underscores the fact that ethanol ranks low on the list of factors when it comes to fuel economy.
10,000: Estimated number of boats with polyester-fiberglass tanks. If you have one, never use ethanol. Test a sample at each fueling with a few drops of dye that disperses in ethanol or water but not gasoline. Better yet, replace your fuel tank, because straight gas isn’t widely available these days.