Thread: SEF Fuel
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Unread 04-19-2014, 05:15 PM
stihlydan's Avatar
stihlydan stihlydan is offline
String Trimmer
Join Date: Feb 2013
Location: Hampton, VA
Posts: 1
Default Sorry to tell you this but....

I can not confirm or deny the octane claim. However I can tell you several things you did NOT know.

First everything regarding Moto-mix is different. The entire formula comes from Stihl and is only packaged by Omni. NOTHING is similar to Tru-Fuel or any other fuel what so ever with the exception of the can used.

Moto-Mix has little to no aromatics. Stihl's MSDS lists Benzene at <.5% ALL the others have more than 20%. Some as high as 30%. There was a time (I have those copies) when the other companies' MSDS had the contents of aromatics. In responding to this post, I pulled up the latest MSDS sheets and they now have none shown. I know their formulas have not changed. So I can conclude they are getting wise to aromatics and now choose to not show that content.

If you google fuel aromatics you find it is composed of Benzene or may be referred to as aromatic hydrocarbons. These products cause swelling of rubber products.

With regard to what this canned fuel may do if used after other fuels, let me tell you what we have learned in our shop and by personal experience at home as well.

In 2007 I started having a problem with my own gas powered golf cart. Once a month I would get what I call a "brown jell-o" in the carburetor. I would clean it out and a month later it was back. This went on for a year until I decided to use a preservative. You know like Sta-bil or Star-Tron. I used the stuff from Briggs and Stratton. Since using a stabilizer, I have not had the "brown jell-o" problem again.

So I assumed there was something in the fuel that would precipitate out. As long as a preservative was used, it stayed in suspension. Incidentally, I still get complaints about the RED colored Sta-Bil so we only recommend the blue colored one.

Now here's the good part. I have a customer that has a water cooled Kawasaki 2 cylinder John Deere front mount mower. For 17 years never had a single problem with it. 3 summers ago he saw Star-Tron in Lowe's and put it in the mower. Within 2 hours the mower stopped and would not restart.

We took it in, cleaned the carburetor, replaced the fuel filter and lines and it has been good ever since. So what? We figured that because he never used a preservative, the "brown jello" I spoke of had simply coated the inside walls of the fuel tank. All was status quo until he put the Star-Tron in it and that washed off the brown jello and sent it head long into the carburetor.

So we recommend to anyone that has equipment that sits for long periods of time like power washers, tillers, generators, leaf vacuums and such. That they always use a "blue" preservative in all the fuel. We also see the brown jello in mixed fuel units so we recommend 100% of fuel used in them always contains "blue" preservative. I keep saying blue cause it seems to us the red Sta-Bil does not work with ethanol. Even though there is one that says it does and another that does not say ethanol on it, why chance the confusion. I know the blue one works. We have been using it for 5 years in our shop now without incident.

So to the gentleman that asked about using the canned fuel after regular gas, I say be careful that it does NOT wash contaminate out of the tank. The contamination may be purely age related. It could be area of the country as in different fuels. It could be heat related. We simply don't know.

I want to tell you some more about preservative and fuel. For example, fuel begins to break down 30 days after it is refined. Now no one can say that on a certain day fuel is useless. But, remember this. Once fuel has gotten to a certain point in the break down process, no amount of preservative is going to slow the process down.

So that means, you must put preservative in the fuel the moment you buy the fuel. Now you will get longer life to the fuel as long as the container it is in is air tight. You want a laugh, read the packages of Briggs & Stratton fuel preservative. It states it keeps fuel fresh for up to 3 years. Yeah right!

When the fuel is subjected to air, it's life is significantly reduced. Yeah it is longer with the preservative then it would be without it. But once you put it in a piece of equipment, the life of the fuel with preservative goes way down.

How far down, we tell people to be safe, don't leave it in equipment more than 30 days. Remember gas tanks on devices are not air tight. If they were, the engine could not draw the fuel out of the tank. Now if the fresh, preserved fuel is in an air tight container, you can keep it for 6 months. To be safe, no longer.

NOTE: Stale fuel used in a 2 cycle engine, or in a hybrid like Stihl 4-mix, will wipe out the piston and cylinder. Even though the engine starts and appears to run like normal.

Here's another tidbit of info. Plastic fuel cans deteriorate and put little (almost microscopic) bits into the fuel. This causes clogs in the carburetor. So it is recommended to replace the fuel can every 4 years or so.

I was having to replace the carburetor on my Stihl trimmer every year. I'm lazy and I get them cheap so I don't feel like cleaning them or rebuilding them. Since changing to Moto-Mix 3 years ago, I haven't done anything to the trimmer.

Here's another piece of news that I have not confirmed. I heard that in the ground tanks at gas stations, the concentration of ethanol usually exceeds what is pumped into it. For example I heard (again not confirmed) in a 10% ethanol tank, the concentration of ethanol can rise to as much as 40%.

One last morsel and I will leave you. What happens with 15% ethanol and higher?

The heavier ethanol drops to the bottom of the tank. Now the bottom portion is straight ethanol. So since most fuel systems draw from the bottom of the tank, guess what gets burned? Straight ethanol until it's gone.

Now guess what happened to the gasoline above the ethanol? When the ethanol separated out, it took the remaining gasoline down 3 octane levels. So if you started with 87 octane, it now has 84 octane. Try using that in power equipment in the summer. Pistons will melt.

Put that in your tank and smoke it folks. Incidentally you can write to me at
Snapper Pro, Exmark, Husqvarna and Stihl dealer. In the bus since late 70's. BS in electrical engineering. Shop located in Southeastern VA.

Last edited by stihlydan : 01-28-2016 at 09:44 AM.
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