I have no choice were I am at, all we have is E10. I have to use it in my mowers, weed eater, leaf blower, ect.... Just do not let the fuel get old, just purchace the amount of fuel for a few weeks. Do not buy 5 gallons of fuel if you only use a gallon every 2 weeks.
As for the old gas in the boat, I pump mine completly empty in the fall. I have a aftermarket MPI kit and I simply disconnect the fuel line after the separator, hot wire the pump and fill up 5 gallon containers. I put what little gas is left in the truck and car. If the gas is 6 months old that is a hard call, you may blend it 50/50 in the car with premium? Running it through a water separator may help but may not. After my experience I am very carfull with the age of the fuel.

This thread is giving me nightmares! I just found this online:

Since 1997, Minnesota has mandated 10% ethanol in gasoline. On May 10, 2005, Governor Pawlenty signed E20 legislation which doubled the required percentage.

I just called the gas station I use for the boat, they said they are still at 10-percent. Everyone here is talking about 10-percent, I can't imagine what 20 would do.

Alot of the issues we get with boats vs automotive is because the fuel system in autos is basically sealed with vapor canisters and such. This really limits the amount of moistier that is asorbed into ethynol. Plus 99% of the autos get fuel used a shorter time frame.

Do you have Merc MPI engines? I have been told if you add a return line to your fuel system it helps the vapor lock. I have a Holley MPI with return line and never had vapor lock. I think it has somthing to do with the temp of the fuel rails gets to hot without the cycling fuel.

my gas is about 8 months old.. 91 octaine.. not sure if the mechanic put in stabilizer.. 100 gallons in the tank... Would you empty the tank? new 520 hp engine in my boat... this is scary to me... we have 10% ethenal in our gas here

I would put at least half out and run it in the cars and put stabl in it now if not sure

Ran across this post today. I got prolly 3 quarters of a tank with ethanol that sit since novemeber. I am going to blend in some of 102 or 110 race gas to spice it up some. Raise the octane level and lower the ethanol/water content levels. This is a good consideration for everyone.