If you leave it in your airplane, it isn't stored in a tightly closed
container, though, is it? It sure isn't in mine!

Um, well, it's as tightly closed as any vented tank can be. Even gas
station storage tanks aren't sealed tight, or they'd be unable to
expand/contract with temperature changes.

I have noticed the difference and found that mogas, having sat in an
airplane for a few months, is a lot harder to get going than equivelant
Avgas in the same airpane.

I have never noticed the slightest difference. Now, of course, I
don't let my plane sit for months, or even weeks -- but my motorcycle,
convertible, lawn mower(s), lawn blower(s) and vacuum, and snow
blower(s) ALL sit for many months, unused. No problemo starting or
running in the spring/winter.

Also, we have a shell petro-chemical engineer in our circle and he tells
us that the aromatics in mogas evaporate more readily thuus causing the
degradation in quality.

Again, a cite? ANYTHING in writing, ANYWHERE about this problem with
mogas?

For ten years I've been hearing "my buddy the engineer told his
brother that..." -- and, after a decade (and over 9,000 gallons of
trouble-free mogas in our planes) I'm simply not buying it anymore
without SOME kind of evidence.

IMHO, as with so many of these things, we desperately want to believe
that gasoline that costs 25% more is really better in some tangible
way. I have seen no evidence of this, at all, over a decade of use.
That would zero, zilch, nada -- no difference.

Of course, to that end, there are STILL people out there who will pay
a premium for high-octane gasoline for their cars, despite
overwhelming evidence that this is a complete waste of money. The
oil companies just shrug their shoulders, pocket the extra dough, and
keep making commercials touting how their brand "cleans your
injectors", or some other BS.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"