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I didn’t watch the video so I assume he just does the math and says ethanol is a net negative from an environmental perspective, but its also super annoying for

I didn’t watch the video so I assume he just does the math and says ethanol is a net negative from an environmental perspective, but its also super annoying for carbureted small engines since it turns to resin after sitting for some time. I live in a major city and can’t even find 100% gasoline anywhere.

fuzzfactor 5y ago
Negatore to the resin. It really can be considered more like varnish but it doesn't come from the alcohol itself. Chemicals like methanol and ethanol do not polymerize whatsoever in your fuel system. The varnish at the bottom of your tank is the result of long-term gum deposits from the less-stable olefinic content of the gasoline hydrocarbons. These are the reactive components which are subject to self-polymerization and oxidation over time. The gum which is already formed but still dissolved in the fresh gasoline is known as the "existent gum", and that is measured separately from the additional gum that is expected to form as the fuel ages known as the "potential gum". If the fuel is not allowed to evaporate very much or be in storage for very long almost all of the limited gum content will never separate from pure hydrocarbon fuel which acts almost as an ideal solvent for these hydrocarbon by-product polymers. The very small amount of the heaviest gums which do end up having a number of grams build up after literally tonnes of gasoline consumption are the varnish that can fully coat the bottom of your tank and it can look pretty ugly, while not causing a problem since it's been largely engineered around for decades. The fuel pump and fuel filter can handle little pieces of varnish that come loose and the coating can stay harmlessly there, until you add alcohol for the first time. The alcohol has stronger solvent properties for the varnish and a lot of it can all come loose at once and make the whole tank cloudy, then clog up the fuel filter leading to starved engine performance and low power. So you change the fuel filter and you get the cleanest tank you've had in a while.
- porknubbins 5y ago
  Right, you mentioned evaporation and long term storage which is the exact problem I am dealing with. Carburetor float bowls are basically open to the air and begin evaporating quickly, especially in the heat and the pilot jets which have tiny openings become completely blocked. Stabil helps but its hard to remember when to use it.

fuzzfactor 5y ago

Negatore to the resin. It really can be considered more like varnish but it doesn't come from the alcohol itself. Chemicals like methanol and ethanol do not polymerize whatsoever in your fuel system. The varnish at the bottom of your tank is the result of long-term gum deposits from the less-stable olefinic content of the gasoline hydrocarbons. These are the reactive components which are subject to self-polymerization and oxidation over time. The gum which is already formed but still dissolved in the fresh gasoline is known as the "existent gum", and that is measured separately from the additional gum that is expected to form as the fuel ages known as the "potential gum". If the fuel is not allowed to evaporate very much or be in storage for very long almost all of the limited gum content will never separate from pure hydrocarbon fuel which acts almost as an ideal solvent for these hydrocarbon by-product polymers. The very small amount of the heaviest gums which do end up having a number of grams build up after literally tonnes of gasoline consumption are the varnish that can fully coat the bottom of your tank and it can look pretty ugly, while not causing a problem since it's been largely engineered around for decades. The fuel pump and fuel filter can handle little pieces of varnish that come loose and the coating can stay harmlessly there, until you add alcohol for the first time. The alcohol has stronger solvent properties for the varnish and a lot of it can all come loose at once and make the whole tank cloudy, then clog up the fuel filter leading to starved engine performance and low power. So you change the fuel filter and you get the cleanest tank you've had in a while.

porknubbins 5y ago
Right, you mentioned evaporation and long term storage which is the exact problem I am dealing with. Carburetor float bowls are basically open to the air and begin evaporating quickly, especially in the heat and the pilot jets which have tiny openings become completely blocked. Stabil helps but its hard to remember when to use it.