In the past 30 years we have become a nation that overproduces fuel related crops (dry corn and sugar beets) more for ethanol production than regular food for human consumption. Soybean crops have also become popular in recent years to produce bio diesel to mix with regular diesel.
Both of these industries for profit approaches have been destructive to both the environment and the longevity of equipment that relies on these fuels.
Ethanol blend gasoline is hygroscopic, so it collects moisture out of the air and forms water droplets that sits in the bottom of fuel tanks and fuel bowls when left sitting for long periods. In the short term it will stay suspended in gasoline and burn without issue. It is the sitting for long periods that causes it to degrade, especially in hot climates. Moisture and aluminum carburetor housings do not play well together.
The best solution is to drain all the gasoline from your equipment and put it in your vehicles to use instead of letting it go bad from sitting for long periods.
With bio diesel the problem comes with gelling and loss of lubrication properties that are natural in diesel fuel. Older mechanical injection pumps require a heavy dose a lubricity additive to keep it operational. (I know this the hard way after 2 injection pumps locked up within a year on my old backhoe)