Small engines hardly have them, and in general overall the “sealed” open point is the carbon cannister in vehicles which allows air and commensurately water vapor, in.
That's why I said "easy fix".
Either run the tank dry after use, or shut off the fuel and run the bowl dry, and screw a piece of fuel proof plastic under the cap when not in use.
...in general overall the “sealed” open point is the carbon canister in vehicles which allows air and commensurately water vapor, in.
We don't have E85 that I know of here in Maine, but we do practically live under water with all the rain and high humidity.
I haven't seen any huge issue with gas going bad in modern cars. As with the gas stations, which are open to the atmosphere with un-filtered air inlets, cars in regular use, get by with a high fuel turnover (with normal driving).
Any relic...better take some measures. As for small engines, I have 30 year-old snowblowers and lawn mowers that continue to run just fine.
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