I never have any fuel problems, and I never use any additive of any kind.
And I used 1 1/2 yr old 50:1 gas off and on all summer in a little tiller....started 2nd pull every time.
Next spring I will (try to) fire it up on the same gas,....we'll see what happens.
But I'm the one that removed the carb bowl off my s40 for the sole purpose of seeing the Ka Ka left in the bottom after 4 yrs of e10. Problem was, it was spotless,....I still have the pics I posted.
Truth known, e10 already has the additives needed to keep the fuel system clean. Thats why we don't see any cars w/ sophfisticated F/I systems parked all along the roads everywhere.
But I'm just an amazing person,....because I'm the only one running a vac petcock that doesn't have any fuel problems !