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On Fri, 30 May 2014 09:47:12 -0400, "Ed Huntress"
wrote:



wrote in message
...

On Thursday, May 29, 2014 3:43:15 PM UTC-4, wrote:
wrote:
snip

Your Stihl will work fine on ethanol blends. Mine does.
And I've been using ethanol blends in my Husquavarna
since the late 70's and the only issue was replacing
the rubber fuel line going into the carburetor.

Good to know, Thanks.
It might be good for those engines that can burn "most anything"
to advertise that fact.

George H.






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Hi George,

I just stopped in to see if my cross-posted reply to rangersucks ever got
through, and here I run into one of my favorite subjects... Sorry for the
messy posting but I don't have a newsreader anymore and I have no reason to
get one. This is a one-shot.

I can't stick around to get into this, but you seem to be genuinely
interested, so here are some facts that may help or confuse you, depending
on which way you tilt:

Ethanol will not gum up a carb or an engine. But they often mix it with
low-grade gasoline (under 91 octane, among other, bigger issues) and that
gas *can* crap your engine. It does seem more prone to varnishing the carb
jets, but that isn't because of the ethanol.

Ethanol will not do damage to a carburetor, large or small. *Methanol* will
do damage to aluminum or zinc (or brass, I think) if it's left in the
carburetor bowl too long. Race cars that burn methanol generally drain the
carbs, and often the tank, between races. The ethanol-damage myth probably
is a carryover from admonitions about methanol, dating back to the 1930s.

Ethanol *will* eat some kinds of gaskets. I got little bits of damaged
O-rings in my lawnmower carb soon after they started with the ethanol in
pump gas. I had to change gaskets and blast the carb with carb cleaner
every
season for a couple of years, until I learned what was happening and sought
come ethanol-resistant gaskets. Newer ones seem to have solved this.
Obviously, the material in automobile gaskets is immune now.

The MIT report on efficiency with ethanol was misrepresented in the posts
here. I read all 61 pages of it, and the story is that up to 20% or so
ethanol will allow enough BMEP from boosted compression to increase
efficiency in a high-speed highway cycle, with long runs above 60 mph and
peak over 80 mph, if you are comparing a very small turbo engine with a
much
larger normally-aspirated one. That engine cycle is not used in EPA
city/highway cycle comparisons. In normal driving, the MIT report says,
there is almost no difference -- and required boost can be achieved with
spark retardation that is so low it has almost no effect on performance. At
some point, the lines of volume efficiency cross, where the lower caloric
content of ethanol is compensated by the very high turbo boost that ethanol
allows. The report is worth reading.

FWIW, I read SAE engine-research reports at least once or twice a month.
That's where most of my info comes from.

Happy motoring...

Ed Huntress

I have been told in the past that ethanol was added to low grade
gasoline in order to make it suitable to burn in cars. And maybe
that's the difference. Lower grade gas that has added ethanol is
actually the culprit. When I use the ethanol free gas it is a higher
grade and so does not "gum up the works".
Eric

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I don't know which came first, but my (unresearched) understanding is that
they can use a lower-grade gasoline to mix with ethanol because the ethanol
boosts the effective octane rating. It also is conventional wisdom (again,
unresearched on my part) that low-octane gasoline may be low on detergents
and other additives.

Before it was required, there was some use of ethanol in gasoline to replace
the octane-boosting effect of tetraethyl lead, which was outlawed in 1995.

All gasoline sold as motor fuel in the US also has been required to contain
detergents since 1995 -- a result of previous maintenance problems with fuel
injectors. Whether they short-change the additive quality of gas they mix
with ethanol now or not, I can't confirm with any authoritative data.

Ed Huntress