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I just invested in a very nice 2-cycle string trimmer and I want it to last. I have always used stabilizer in my fuel for my 4-cycle lawn mower. I know that ethanol attracts moisture and the stabilizer does not let the water separate and sink, thus rusting out components. I also know that ethanol used to break down seals and fittings, but that manufacturers use better material now that are okay in the presence of ethanol.

Is using a fuel stabilizer and mixing the oil myself just as good as using an ethanol-free fuel? I have read some reviews of the pre-mixed fuels where a lack of lubrication (caused by quality control at the manufacturer plant) have caused pistons to seize up in the cylinders.

I don't care about the cost of the pre-mixed fuel as I wouldn't use much in an entire season; the question is more about the benefits and risks.

Evil Elf
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  • Your question is really about risk, and is therefore primarily opinion-based. Voting to close. (No offense.) That said, I'd prefer to mix myself using oil and stabilizer that I've selected. – isherwood May 11 '16 at 14:55
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    I am hoping to get actual experiences to show facts instead of just opinion. Hopefully, some small engine mechanics chime in. In other words, determine the actual risks. – Evil Elf May 11 '16 at 15:10
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    @isherwood I fail to see how risk is opinion-based. Either it's safe, or it's not, or it's safe as long as you use certain precautions. – Mast May 11 '16 at 19:32
  • *Nothing* is either "safe" or not. Everything has relative risk, and everyone makes their own decisions regarding what level of risk is acceptable. Heck, the definition of "safe" is wildly variable. What list of precautions makes that risk acceptable? It's a subjective question that allows only for subjective answers. – isherwood May 11 '16 at 19:52
  • Is ethanol damage prevented with the same effectiveness using fuel stabilizer vs ethanol-free gas? – Evil Elf May 11 '16 at 19:55
  • That's an objective question, but only to the extent that we know exactly what products are involved and have all the necessary scientific data. At that point we're a good ways away from "home improvement". :) – isherwood May 11 '16 at 19:58
  • In my experience, the pre-mixed is better because it has no ethanol, and is all-around more stable long-term. One caveat is that it's pre-mixed to 50:1, which the EPA specifies. This allows just about the bare minimum of lube for the engine. So ideally you'd add a bit extra to the pre-mixed stuff and bring it to like 40:1. – Jon Fournier May 12 '16 at 18:09

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Nothing is guaranteed but I think the odds of you messing up the fuel/oil mixture yourself are greater than getting a bad batch from the factory. So I would say yes, the pre-mixed fuel is a safer bet. Also if you buy pre-mixed fuel there is less risk of water/dirt getting into your gas cans.

However I personally think it's not worth it. Buying pre-mixed fuel removes one possible source of problems but it does not guarantee trouble-free use year after year. You will still want to perform basic small-engine maintenance like emptying the fuel tank at the end of the season, checking the air filter periodically, etc.

You could do some back-of-the-envelope math to see how much it would cost you to use the pre-mixed stuff and then compare that to the cost of a new trimmer if this one does bite the dust. At a cost of $20-30/gallon it could really add up if you use the trimmer regularly.

Hank
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    I am an engineer and slightly OCD (joke here), and I have learned that if you want anything done right, you have to do it yourself. In regards to messing up a mix, I consider this impossible. I do agree with the cumulative cost vs replacement cost of equipment needs to be considered. I also worked as a quality engineer in an automotive part plant so I know firsthand how easily bad product can make its way into the consumer's hands. – Evil Elf May 11 '16 at 15:13
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    It'd be less about getting a new; bad batch from the factory... and more about getting a can with some unfortunate history, like it sat at a warehouse for 2 years, or was left inside a shed or vehicle for an extended period, and heat from solar gain chemically altered it. – Harper - Reinstate Monica May 11 '16 at 17:22
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Not all gasoline is the same... summer blends, winter blends, exxon brand, BP brand, etc. All gasoline is the same (fungible) in the pipeline; some gas stations have direct lines, while others rely on trucks which deliver gasoline from a local terminal. In either case, treatments are added to the fuel just prior to being sold to the user.

That being said, ethanol-free fuel tends to burn better (especially in 2 stroke engines) than E-10 (despite the additives used to compensate for ethanol). Ethanol is thin and does interfere with lubrication- so some of the additives are oils, to help with that issue. Unfortunately, quality is variable. If you search online, you can probably locate a gas station that sells ethanol-free fuel somewhere. That's going to be the safest bet.

Also, engine quality makes a difference. Please excuse the product recommendations, but Stihl makes the best weed-trimmer and Kubota makes the best lawn mower. This is not really an opinion; it is an observation of what withstood the most use and abuse from a commercial landscaping business.

Ben Welborn
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  • Downvoter, I have more first hand experience with this than anyone would ever venture to guess. From copious chemical analyses of gasoline to being a mechanic for a very large landscaping business. Please, explain why you voted this answer down! – Ben Welborn May 11 '16 at 15:45
  • FWIW, at least locally for me, if you want ethanol free you need to buy the 91 or 93 octane gas. – Steven May 11 '16 at 16:34
  • @Steven 91 and 93 octane have 10% ethanol. 91 is a mix of 93 and 87. There are only two tanks at a gas station, 87 and 93. 91 is mixed at the pump as you put it into your car. – Ben Welborn May 11 '16 at 16:58
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    most local stations don't have 93, only 87,89,91, in which case they say 91 contains no ethanol.. again this is what's available locally for me, so it likely differs by region – Steven May 11 '16 at 17:02
  • @steven I believe that someone mislead you. The octane number is actually raised by adding ethanol. So if anything, 91 octane has more ethanol than 87... whoever told you that simply has no concept. But the real answer is they both have 10% ethanol. If you want to find ethanol free gas, look here: http://www.pure-gas.org/extensions/map.html – Ben Welborn May 11 '16 at 17:05
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    @BenWelborn What you say varies by brand. **A lot.** Hard for a person who buys BP only where there is no Chevron... to meaningfully compare notes with a person who has a smartphone app to find the cheapest gas. I do travel a lot and pay a lot of attention, and yes, some brands offer ethanol-free gas, sometimes marketed as their premium. Marketing really is the key to it. – Harper - Reinstate Monica May 11 '16 at 17:15
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    @BenWelborn Very much possible the 91 has no ethanol. Ethanol raises octane, yes, but the underlying gasoline can have higher/lower octane rating to begin with. Premium users may be willing to pay a, well, premium, to have ethanol-free gasoline. Also, states (and countries) have varying laws as to what ethanol must be in (or must not be in), not just the federal US regulations; driving from IL to CO annually I see very different gasolines in each state (and region of state) along that route. – Joe May 11 '16 at 17:34
  • http://www.shell.ca/en/products-services/shell-for-drivers/fuels/shell-vpower/faq.html - they say their highest octane fuel does not have ethanol. – Steven May 11 '16 at 18:17
  • @steven, indeed, canada doesn't ascribe to the political push for E-10. But this was really a question about E-10 which is an american issue. If you live in canada you are lucky not to have to deal with running a weed-eater on E-10. – Ben Welborn May 11 '16 at 18:24
  • @harper I hear you reiterate the first sentence of my answer (Not all gasoline is the same...) and I hope that the explanation (treatments are added to the fuel just prior to being sold to the user) was useful to everyone. I would further suggest that everyone should look into the meaning of fungible fuel. I am more jaded by marketing than most, but that's because I have access to laboratory equipment that provides me with real insight- to see through the marketing. – Ben Welborn May 11 '16 at 18:41
  • @Ben Welborn, nobody needs to explain a down vote (it wasn't me though). Diverse participants express their opinions of the various answers by voting, and the posters know (or should know) that the "score" is based on public opinion. It really doesn't matter, that's why a poster can choose *any* answer as the correct one. oh, and your statement that "All gasoline is the same...in the pipeline" is utterly false, we use a marker fluid slug ahead of and behind each gasoline shipment through a shared pipeline so we **know** it is our product. It is only fungible because it meets *minimum* spec. – Jimmy Fix-it May 12 '16 at 03:27
  • @JimmyFix-it you are wrong about slugs; thanks for explaining why you voted this down. You might have been thinking of pigs, but even so, you are confused as to their purpose. Please read about pigs: https://en.wikipedia.org/wiki/Pigging and slugs: https://en.wikipedia.org/wiki/Slugcatcher and pipeline transport: https://en.wikipedia.org/wiki/Pipeline_transport – Ben Welborn May 13 '16 at 13:05
  • @JimmyFix-it When gasoline is extracted for use from the end of the pipe (which is thousands of miles long), it is replaced with more at the front. A pipe is a one lane highway (first in = first out). When a company pays for fuel at the end of the pipe, they get what they get. Their money pays for more gas to be put into the pipe plus a fee. Fungible does indeed mean that the gasoline must meet minimum specification. The the gas going into the pipe is not better than the minimum quality, because it would be expensive and wasteful, since it will be bought by the next (random) customer in line. – Ben Welborn May 13 '16 at 13:06
  • @Ben Welborn, I coordinate pig launching and receiving. The "slug" I refer to is a fluid with a different specific gravity than the product, sensors detect the fluid so the pipeline operator knows when my shipment ends and a competitor's begins; thus he can initiate the proper pipe switch/routing. Customers are not *random* and they will not accept a competitor's product if they paid for mine, they don't "get what they get" (unless they specifically purchase from a marketing pool). You may be expert at some things; modern fuel refining, transport, and marketing maybe not so much. No biggy – Jimmy Fix-it May 13 '16 at 16:51
  • @JimmyFix-it Regarding "modern" fuel refining, I've made gasoline from a few stuffs. I know that various states "require" different additives, and that gov't is on the oil company's pay roll. Refineries haven't changed in 20 years. To make 93 supreme, you add TAME, PEA, and Tolulene to regular 89 (E10). When you look at my 1st answer it should be obvious that I know special ethanol free fuels make the trip, and boutique motor fuels too (was 6, now 20 varieties). But over 95% of gasoline in the USA is E10, not to mention the ethanol added without being reported. Gasoline is simple, shiny sells. – Ben Welborn May 14 '16 at 00:08
  • @ Ben Welborn, TAME hasn't been used for years and years (contains methanol and is banned just like MTBE). So much for "haven't changed in 20 years", you don't know what you are talking about. I **make** gasoline, jet and diesel fuel for a living. Make a deal with you, I won't tell you about your area of expertise if you don't tell me about mine? Gosh your profile is so extensive too, I bet you are very impressed with yourself. The people who most impress are those who want to learn, not those that insist everyone learn from them, especially when they share ignorance. Jeez enough already... – Jimmy Fix-it May 14 '16 at 04:59
  • @JimmyFix-it Wow, that must have been a long training video! I'm in awe of your expertise! Gasoline refining has not changed in 20 years. This additive or that, is no biggy. I actually know what TAME is (and how to make it) and maybe it is banned (a legality). But TAME does not "contain" methanol. TAME is it's own chemical. The only chemical that contains methanol is methanol, and methanol is added to gasoline too! So, TAME is banned, OMG, I guess they'll settle for using DIPE. Seriously, any moron. Oh, and my profile most certainly is not extensive... shows only a fraction of my experience. – Ben Welborn May 14 '16 at 16:49
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My chainsaw starts every time ever since I switched to the pre-mix 2-stroke gas without ethanol, even after leaving it in the shed unused all winter.

Jimmy Fix-it
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