Stihl says " Look Before You Pump Gasoline for Outdoor Power Equipment"

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What it does in a 2 stroke engine im not that well edumacated but I do know a bit about it in the automotive side of it. I have many friends that run E-85 in their modified cars (supercharged and turbocharged mainly) Ethanol has a much higher octane rating then gasoline but also burns cooler compared to gasoline so make what you want out of that info. It takes more ethanol mixed fuel to create the same air/fuel ratio then straight gas. In the case of E-85 in automobiles it takes somewhere around 30% more fuel because of the lower BTU output to get the same air/fuel ratio that you had with straight gasoline in a naturally aspirated engine and even more when you get into forced induction. for instance If you try to run E-85 in a vehicle that wasn't designed to run it, you will get lean bank engine codes that will most likely put it in limp mode or cause serious detonation.
Most cars that can run high alcohol blends or straight alcohol have a compression ration of 14:1 or more or a supercharger or turbocharger. My car engine has a ratio of around 8.5 to 1 or thereabouts. Even if it runs on ethanol it doesn't produce the power that pure gasoline will. On a chainsaw you're lowering the power by adding oil then you're lowering it more with alcohol added.
 
Most cars that can run high alcohol blends or straight alcohol have a compression ration of 14:1 or more or a supercharger or turbocharger. My car engine has a ratio of around 8.5 to 1 or thereabouts. Even if it runs on ethanol it doesn't produce the power that pure gasoline will. On a chainsaw you're lowering the power by adding oil then you're lowering it more with alcohol added.
The straight alcohol part would be racing applications and the fuel most likely Methanol. Your 14:1 is probably about right for the racing methanol. My 2012 F150 has a flex fuel logo on the back. The naturally aspirated 6 cylinder and the 5.0 v8 have this logo. It is compatible with E85, I guess about 85% ethanol. It is actually a tiny bit more powerful using that fuel from reading on the F150 forum and maybe also the manual. It uses significantly more to go a mile, like 12 mpg instead of 20. I have yet to drive by a station that sells it. Why all the fuss about E15 when I have yet to try out a tank of E85 is puzzling.

About the air fuel part of the quote above yours, the numbers used are generally by weight and jets for alcohol are significantly larger if the same carburetor is even suitable.

Fuel pumps around here are generally marked contains up to 10% ethanol. Some are marked contains 10% ethanol. I have not yet seen any E15 pumps. Occasionally one reads of excess water or excess ethanol due to some error in the supply chain.
 
Ethanol is dumb and has no purpose other than to funnel public money to well connected individuals through big ag corporations - it takes more energy (from oil) to make it than it provides, and ethanol has less energy per mass (and I think volume) than gasoline. But no one is surprised by corruption anymore.

Still, I'll get my fuel from the local station, and at the moment while this scam is still going on that means E10. The only problem I've ever had with it is vapor lock, but I've mostly learned to deal with that. My saws, ported or not, have all run 87 octane E10 at 40:1 for years - then again they're not worth anything financially, so not much risk for me.
 
The trouble with non ethanol is you really don't know what your getting, could have ethanol in it or maybe 2 years old at a slow gas station. Over here we have enough snowmobiles that run non ethanol to keep the supply kind of fresh. No troubles in my saws so far. Steve
Curious as to why you can trust E fuel & not non E ? is it just the storage time The part of France where I live, No fuel of whatever brand contains any E, so I guess I'm spared any problems related to E fuel. 2 smoke motors are renowned for if you want the best performance available the carb settings should be adjusted at hourly rather than daily/weekly settings but as a saw in normal trim is not that picky it is often over looked or considered necessary
 
I actually looked up the individual parts in the carb rebuild kit for my stihl. The maker said the synthetic parts were not sensitive to ethanol. That made some sense given what I was seeing when I disassemble the carbs on my 2 cycles. That in turn made me aware of the crappy paper gaskets they give in the kits. I think they are actually what fails, and of course as soon as they leak air, the carb fails to function properly.
 
A friend of mine that is employed in an outdoor equipment company thinks the reason for the Stihl statement is to try & get Joe Public to change to using their Tru/Aspen type fuel which at present the price makes possibly them more profit? May not be fact but it has a ring of truth
 
Getting non ethanol gas is not feasible for me. Concur with the others in this thread regarding how ridiculous gov't subsidized and mandated ethanol is.
 
Why all the fuss about E15 when I have yet to try out a tank of E85 is puzzling.
I'll preface this by saying I am actually a big fan of ethanol (in no way political, I just think it's a superior fuel) but the real problem with it comes from running so little of it in gasoline. I have many of my own equipment and cars rejetted and retuned to run e85, and I store my saws and small engines with e85 in the tanks and don't have problems, if any moisture gets in it just absorbs into the fuel and is burned off. With only 10% ethanol in the fuel once that ethanol is saturated with water (doesn't take too much) it drops out of the gas and will corrode and mess up carbs, with straight e85 I don't get issues unless lots of water physically enters a carb from rain or spraying with water. I have had e85 in my old homelite xl12 for like 10 years and i've never had an issue.

As an ethanol fan who has been using it for 10 years+ I do understand the need for 100% gas, and even I would love to have it easily available, but I'll never buy those cans at the store.. Just run your equipment and you won't have fuel issues. With pure gas it may take a year or two to really gum up, but with ethanol you really ought to run your engines at a minimum of every 90 days, more if it's wet and condensing like spring with snow melts.

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Can't say I've ever seen a fiberglass fuel tank, but I bet it would fall apart in the presence of pure gas too. Now, an aluminum below deck tank will grow some white paste, sometimes enough to block the pick up tube, when water is present. The hydroscopic nature of ethanol blended fuels ensures a good supply of water. Not too much of an issue though, plastic fuel tanks have been installed in boats for the last twenty years or so. Most boats with aluminum tanks are rotted junk and long since scrapped out.



My Mom is the Original owner of a 1969 Stevens 17' Flat bottom, V-Drive, essentially an SK class racing hull with recreational seating, it has 2 7 gallon (IIRC)tanks that are fiberglass, it will be 50 years old this year, and both tanks are holding up very nicely. A friend of the family was a Stevens boat dealer, and we had several friends with Stevens Boats, Fiberglass tanks were very common in them, and I NEVER heard of any problems with the fiberglass tanks.

Many service station tanks are Fiberglass, and those are often around 10,000 gallons.


Doug :cheers:

ps, Yes, I Know this is an OLD thread, I'm not the one who revived it;)
 

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