I had 15-gallons in the vented tank since Aug 2016 (9 to 10 Months)
I have the test tube type tester that tells alcohol percentage, but not sure how to tell how much water it had absorbed?
I may be having some other issue wit the carb, but right now I am thinking the old fuel?
The problem is the engine won't idle right, and when I punch the throttle the engines seems to go lean? Once the RPMs come up it seems to run fairly good. This is in comparison to last year. No changes were made, and last year it would blow the tires off, now it wants to fall on its face?
Have you taken the carb apart? Sitting that long the fuel in the carb will absorb water. That water in the bowls will cause corrosion. that maybe plugged some of the bleed passages or even is obstructing the jets partially?
When my carb is going to sit for a while I drain it and spray wd40 to protect the insides.
Also when e85 sits in plastic jugs for a long time the gas component (15%) will evaporate as noted by cab and others on here. Your tune maybe off if it was close to being lean before.
More ethanol % needs bigger jets.
It's not as corrosive as methanol but it will attack bare aluminum over time, especially if there is water involved!
Don
