Gas stabilizer for small engines - snake oil?

[knowlittle]

I have a gas pressure washer and a gas string trimmer. Some recommend gas stabilizer (Sta-Bil for example) and some say it is a snake oil. Would petroleum engineers educate me, please? Thank you.

 

[Compositepro]

If you will not be using these items for a while, drain the fuel. Stabilizers do work to prevent varnish and gum formation due to the oxidation of fuel components that contain double bonds.

 

[knowlittle]

Thank you. I have a related question. Does the stabilizer also prevent ethanol containing fuel from ethanol related problems in small 2 cycle engines? Or has nothing to do with it?

 

[Compositepro]

Probably yes, but only if it says so on the label. Isopropyl alcohol (IPA) is the ingredient that will increase the solubility of water and ethanol in gasoline. From hard experience, I have learned to not use ethanol containing gas in lawn mowers or chainsaws. Gasoline must be stored in tightly sealed (non-vented or breathing) containers. Breathing of the headspace due to temperature changes, causes the more volatile components to evaporate, and moisture in the air to be absorbed by ethanol, which results is phase separation.

 

[EdStainless]

Small motors I drain (and run dry). Large ones I fill the tank (with non-E fuel) and I add a stabilizer since the machines are stored in unheated spaces. For me the size is easy, I have a few machines with tanks smaller than 2Qt, and a couple with tanks >2gal.
I use Sta-bil.
The issue is that over time water will collect in the fuel (due to daily heating and cooling). Your options are either to add alcohol to combine with it or let it settle. I have had better luck with the first option.
Everything that I own is new enough that it is rated for use with E-10 so a small amount of alcohol isn't going to hurt too much.

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P.E. Metallurgy, consulting work welcomed

 

[knowlittle]

Thank you for the notes. I cannot find E0 in my area. I will use stabilizer, empty after season, etc. Thank you.

 

[Compositepro]

In my area if you want non-ethanol gas you often have to buy the premium grade.