I know fresh fuel is better than stale.This is an issue to be concerned with Ethanol free or E10.
I bear the extra burden of having gas tanks that are realy too large for my needs. I have two (2) x 27 gallon tanks. I try to keep them at least 3/4's full to reduce condensation and I try to alternate which tank I am using in an attempt to add fresher fuel from time to time to both tanks..
Prehaps, I should just run the one on the drivers side "dry" and not refill it until this fall. I will most likely make enough trips in the next month or so to use all the fuel in driver side tank up.
I try to run my boat at least once a month and when the bite is o,n I wish that number was about 5 times a week.
I have a clear understanding that my 2008/09 or whatever Merc have fuel lines designed to handle the ethanol blends. I do not think that ethanol produces the same power that gasoline does, but I could be wrong. I feel like I have seen a mileage drop off when using 10% ethanol in my truck. My truck can handle E85 so I don't worry about E10 blends in my truck all that much. My boat motor is not designed for E15 much less E85. I would rather have E0 in the boat and have less condensation issues.
I choose to run gas with additives HOPING for enhanced stability and reduced condensation. I would rather try something than do nothing and hope for the best.