OK, I have to tell the truth!

[seasick]

I often state on this forum that at my club, I rarely see true phase separation of ethanol fuel that is not caused by excessive water intrusion.. In 99 % of the cases, water intrusion was the culprit, and not the 'condensation' theory per se.
I may have to adjust that 99% stat just a bit. We actually had a boat recently that had separation of the fuel. The boat had been sitting for several years, 3 or more and had not had fuel stabilizers added that we are aware of. The motor needed to have it's carbs cleaned in order to get running again but it is not clear if that was due directly from trying to start with the bad fuel or just due to the amount of time the motor sat with fuel in the carbs. Of course the fuel had to be removed too.
So, next time I chime in and say that I never see true phase separation just due to sitting, remind me that I have

 

[beachbum]

I agree, I think most /all separation is caused by water/moisture intrusion. I have had gas sitting in gas cans(snow blower, etc) in the back yard for two years and no separation.

None the less, I treat my boat fuel all year round with Stabile and startron.

 

[GulfSea]

I don't worry about the fuel sitting in my tank. I know what it is and can remove it if necessary. Purchased fuel is where the problem lies. Food for human consumption is dated extensively and regulated. But the date of food in fuel is not; that's where the potential for mechanical disaster lies. I've only had it (phase separation) occur once and it destroyed 2-3 carburetors and trashed an older 2 stroke chainsaw.

Since then, I only buy from high volume gas stations just hoping it doesn't happen again. But the potential remains......

 

[hotajax]

I guess I should count myself lucky. In the town where my marina is, two sources of E-free fuel. 90 Octane in the Marina and 87 Octane at a local gas station.