I try not to let anything sit for long periods of time and I’ve been okay . I love e85 for my red car .
I cleaned the carb on my mower as it had gotten a bit eeehhhh towards the end of the season last year back early this year, and it sat for about a month before I fired it back up again and I had to pull the carb right back off again - just full of green gum. I've never had it go to shit so fast before. I've got about 10-15 gallons of gas that's sat long enough that I think it's going to hang out to get some fires going and that'll be that.