SteveSr
Addicted to ArboristSite
Gas goes bad in two ways.
1. The lighter end hydrocarbons evaporate off, leaving the heavier stuff behind. These lighter end hydrocarbons also are the main octane components, and have the highest vapor pressure. This means they're most likely to escape, and you get reduced octane fairly quickly, even if the fuel will still burn. This can mostly be mitigated with a tightly sealed metal barrier can, which is exactly what it comes in. I did let out a tiny bit of those lighter end
The evaporation of these higher volatility components is what provides the majority of the cooling in these small 2-stroke engines. While flywheel fans and cylinder fins help, 2-strokes are essentially fuel cooled engines. This is why running OLD gas can we just as bad (if not worse) than STRAIGHT gas.