Mogas and microbial growth

Folks,

I have a C-182 with an auto-fuel STC, which I've been operating on Mogas
(along with an occasional fill of 100LL) for several years. Mogas being
unavailable at my home airport, I use a pair of 6 gallon Gerry cans
(plastic) to transport the fuel from a local gas station to the
airplane.

I've taken the usual precautions to keep dirt and moisture out of the
Gerry cans but lately encountered something a bit unexpected: as I was
preparing to fill the cans, I happened to glance inside one and noticed
several patches of what appeared to be mold or fungus. These were dark
brown in color, from 1/8 to 1/2 inches in diameter; there were 4 to 7 or
so of these on the bottom inside surface of each can.

Has anyone else encountered this, and have any ideas on how such
contamination can be prevented? Beyond the obvious concern of fuel line
blockage from this stuff (I've since started filtering the fuel when I
transfer it the cans to the airplane), I'm worried the plane's entire
fuel system may be contaminated. (I peered inside my Bladders with a
flashlight but can't see enough to tell anything.) Is there any sort of
anti-microbial additive that can be used with Mogas, that can
"disinfect" my Gerry cans and/or fuel system? Does this problem exist
with metal containers, or just peculiar to the plastic cans?

I've heard that 100LL doesn't have this problem, due to the toxicity of
Tetraethyl Lead. Perhaps occasional use in the Gerry cans would
disinfect 'em?

Any advice much appreciated! Thanks in advance...

EGM

Economic Girly Man wrote:
: I've taken the usual precautions to keep dirt and moisture out of the
: Gerry cans but lately encountered something a bit unexpected: as I was
: preparing to fill the cans, I happened to glance inside one and noticed
: several patches of what appeared to be mold or fungus. These were dark
: brown in color, from 1/8 to 1/2 inches in diameter; there were 4 to 7 or
: so of these on the bottom inside surface of each can.

I'm not sure what to think about your "diagnosis," but I know I felt a lot
better running mogas after rigging a water-absorbing filter into the pour-spout of the
cans I use. I found just a a bit of water, rust particles, in the fuel sample before
I did this. Now, with the spin-on filter ($25 + some clever engineering to make it
into a pour spout), I never see anything. I don't care what crap is in the can (I see
some particles/water/etc on the bottom).... it never makes it into the tank.

I'm not sure how to deal with the fuel bladders, but I drained and redrained
my Cherokee tanks a few times after I found a bit of contamination in it. If you
truly have slugs of growth, that could be hard to get out (for the same reason it's
bad to leave it it... it'll plug holes/lines). If I had to guess, I'd say your cans
got their growth while sitting empty for awhile with some water in the bottom. I
wouldn't think it would grow in the airplane's bladders (but I could be wrong).

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

I've never heard of anything being able to live in gasoline.

Mike
MU-2

"Economic Girly Man" wrote in message
...

Folks,

I have a C-182 with an auto-fuel STC, which I've been operating on Mogas
(along with an occasional fill of 100LL) for several years. Mogas being
unavailable at my home airport, I use a pair of 6 gallon Gerry cans
(plastic) to transport the fuel from a local gas station to the
airplane.

I've taken the usual precautions to keep dirt and moisture out of the
Gerry cans but lately encountered something a bit unexpected: as I was
preparing to fill the cans, I happened to glance inside one and noticed
several patches of what appeared to be mold or fungus. These were dark
brown in color, from 1/8 to 1/2 inches in diameter; there were 4 to 7 or
so of these on the bottom inside surface of each can.

Has anyone else encountered this, and have any ideas on how such
contamination can be prevented? Beyond the obvious concern of fuel line
blockage from this stuff (I've since started filtering the fuel when I
transfer it the cans to the airplane), I'm worried the plane's entire
fuel system may be contaminated. (I peered inside my Bladders with a
flashlight but can't see enough to tell anything.) Is there any sort of
anti-microbial additive that can be used with Mogas, that can
"disinfect" my Gerry cans and/or fuel system? Does this problem exist
with metal containers, or just peculiar to the plastic cans?

I've heard that 100LL doesn't have this problem, due to the toxicity of
Tetraethyl Lead. Perhaps occasional use in the Gerry cans would
disinfect 'em?

Any advice much appreciated! Thanks in advance...

EGM

I've used autofuel for about 15 years now & have never seen any
contamination in it, or from it, at all. There is lots of gasahol
around here so I have to check each load with the water absorption
test to detect if there is any alcohol present, unless I can buy it at
an FBO. I assume MTBE can be smelled. It is almost universal here in
the midwest. I have metal tanks though.

Mike Rapoport wrote:
I've never heard of anything being able to live in gasoline.

I wouldn't have thought so either, but apparently it *is* possible:
http://www.chevron.com/prodserv/fuel...tm#cleanliness

At any rate, thanks to all who responded to this thread. Got some good ideas to
help solve this particular problem.

Good flyin'...

EGM

Economic Girly Man wrote:


Folks,

I have a C-182 with an auto-fuel STC, which I've been operating on Mogas
(along with an occasional fill of 100LL) for several years. Mogas being
unavailable at my home airport, I use a pair of 6 gallon Gerry cans
(plastic) to transport the fuel from a local gas station to the
airplane.

I've taken the usual precautions to keep dirt and moisture out of the
Gerry cans but lately encountered something a bit unexpected: as I was
preparing to fill the cans, I happened to glance inside one and noticed
several patches of what appeared to be mold or fungus. These were dark
brown in color, from 1/8 to 1/2 inches in diameter; there were 4 to 7 or
so of these on the bottom inside surface of each can.

Has anyone else encountered this, and have any ideas on how such
contamination can be prevented? Beyond the obvious concern of fuel line
blockage from this stuff (I've since started filtering the fuel when I
transfer it the cans to the airplane), I'm worried the plane's entire
fuel system may be contaminated. (I peered inside my Bladders with a
flashlight but can't see enough to tell anything.) Is there any sort of
anti-microbial additive that can be used with Mogas, that can
"disinfect" my Gerry cans and/or fuel system? Does this problem exist
with metal containers, or just peculiar to the plastic cans?

Yes, I had green slime grow all over the inside of the carburetors on my
motorcycle one time when I stored it for 18 months and forgot to drain
the carbs. The best way to prevent this is to not store gas for along
periods of time (6 months or so). The next best thing is to use a
gasoline preservative such as Stabil. However, I don't know if Stabil
is approved for airplane use. I've used it for years in my motorcycles,
lawmowers, chainsaw, snowblower, etc., with great results, but that
doesn't mean it is OK for aviation use.


Matt

Okay, since no one really could say, he is correct, mogas can support
a fungus. You need to filter, filter and more filter.

On Wed, 10 Nov 2004 09:34:54 GMT, Economic Girly Man
wrote:


Folks,

I have a C-182 with an auto-fuel STC, which I've been operating on Mogas
(along with an occasional fill of 100LL) for several years. Mogas being
unavailable at my home airport, I use a pair of 6 gallon Gerry cans
(plastic) to transport the fuel from a local gas station to the
airplane.

I've taken the usual precautions to keep dirt and moisture out of the
Gerry cans but lately encountered something a bit unexpected: as I was
preparing to fill the cans, I happened to glance inside one and noticed
several patches of what appeared to be mold or fungus. These were dark
brown in color, from 1/8 to 1/2 inches in diameter; there were 4 to 7 or
so of these on the bottom inside surface of each can.

Has anyone else encountered this, and have any ideas on how such
contamination can be prevented? Beyond the obvious concern of fuel line
blockage from this stuff (I've since started filtering the fuel when I
transfer it the cans to the airplane), I'm worried the plane's entire
fuel system may be contaminated. (I peered inside my Bladders with a
flashlight but can't see enough to tell anything.) Is there any sort of
anti-microbial additive that can be used with Mogas, that can
"disinfect" my Gerry cans and/or fuel system? Does this problem exist
with metal containers, or just peculiar to the plastic cans?

I've heard that 100LL doesn't have this problem, due to the toxicity of
Tetraethyl Lead. Perhaps occasional use in the Gerry cans would
disinfect 'em?

Any advice much appreciated! Thanks in advance...

EGM