Re: Followup on fuel contamination issues..MOGAS

Mark A. Pearson <wlkabout@...>

Remember, to a politician solving a problem is not the goal. Being perceived as addressing the problem and caring, that's what counts. In the Words of Bono, "We have to do something, even if it doesn't work"


----- Original Message -----
From: Mike Dwyer
To: Q-LIST@...
Sent: Saturday, November 18, 2006 8:31 AM
Subject: Re: [Q-LIST] Followup on fuel contamination issues..MOGAS

Or use the cheapest Mogas you can find (no additives), which is what I
do. 1400 hours on Mogas (several different planes). I am concerned
about the increasing use of alcohol in mo gas tho.

The facts are that E85 (85% Alcohol) gets you only 60% as far as regular
gas. It is estimated that it takes a gallon of gas to make a gallon of
alcohol after you consider the fertilizer manufacture and the tractors
planting and harvesting... So where's the savings? The alcohol can do
some very bad things to our fuel lines and carburetor. I plan to write
my state reps and ask that Alcohol not be added to mogas in Florida and
recommend that everyone does the same for their state.

Mike Q200

Peter Harris wrote:
> Guys here is a report about fuel jell contamination caused by the use of
> mogas, and what to do about it..
> I am passing it on from another list. Be careful. it came from New Zealand.
> Peter
> < Hey Folks
> Finally got a report back from BP technical on the fuel contamination
> we were getting: a translucent gel-like substance blocking the fuel
> filter. The fuel used was BP Ultimate. The plane involved is an Xair
> Hanuman.
> The technician advised the following:
> The BP Ultimate itself showed no signs of contamination or
> deterioration, and met all tested specifications. It contained nil
> ethanol.
> No organic contaminants were present in the sample. (ie. moulds,
> fungi, New Zealanders, etc) ;)
> So, what caused the contamination?
> Apparently, most premium mogas have a significant amount of additives
> which, when left to settle for any length of time (ie. more than 2
> weeks), may cause water to settle within the tank. This water, which
> is in all fuel in suspension, no matter how well it is filtered, can
> combine with the additives to form gel-like substances.
> They felt it may have occurred due to settling of the fuel over time.
> However, they were unsure of the exact cause of the contaminant.
> Their recommendations were as follows:
> A fuel resistant liner within all plastic and fibreglass tanks was
> highly recommended. In fact, he pretty much advised against using
> such tanks without some form of protective insulation between the
> fibreglass/plastic and the fuel. He said it was for this very reason
> that fuel trucks and storage tanks were lined with similar compounds,
> insulating the fuel from the tank. This also applied to tanks using
> They strongly advised against any use of MOGAS in aviation, for the
> very reason such additives are used within the fuel. AVGAS does not
> have such additives, with the exception of lead, and should be the
> fuel of choice, as such a formation would be highly unlikely to occur.
> They were well aware that Jabiru engines can use MOGAS, and were not
> enthusiastic at all on using it in this application.
> Finally, as in marine use, tanks should never be kept full of MOGAS
> for anything more than 2 weeks, due to additive issues. He advised
> fuel should be drained out of the tank whenever possible between use,
> and that at least 1/2 tank of fresh fuel should be added to the tank
> before use.
> Additives such a fuel doctor are unlikely to have any effect on the
> formation of such contaminants. Nor will filtering the fuel with a Mr
> Funnel.
> If you're using MOGAS in plastic or fibreglass tanks, a fuel resistant
> sloshing compound is an excellent preventative measure.
> Ensure no fittings made of aluminium, magnesium or similar non-inert
> metals are in regular contact with the fuel, or fuel lines, as they
> can act as a catalyst with the additives. He mentioned this even
> could occur with brass fuel fittings, although some of the additives
> in the fuel are specifically designed to prevent this occurring.
> Finally, before I get spammed with "oh, you use dirty fuel and don't
> filter it properly", let me advise how we keep our fuel.
> Clean fuel is added each time we fly, at least 1/2 tank. Only fresh
> fuel is added, and not stuff sitting around in jerry cans for weeks.
> All fuel enterring the tank is completely filtered using a Mr Funnel.
> The aircraft is always hangared when not in use, and is never left in
> an environment where water contamination from external factors can
> influence the fuel.
> In other words, we put clean fuel in the aircraft, and didn't cause
> the problem.
> So, whats the conclusion?
> BP themselves advise against using their MOGAS in aviation.
> If you leave premium, high octane MOGAS for more than 2 weeks in your
> aircraft without topping the tank up at least 50%, you will be risking
> separation of the additives, resulting in a similar contaminant,
> regardless of how careful you are ensuring the fuel is clean and
> filtered. Preferrably drain the tank if it's not being used for a few
> weeks, and use fresh fuel the next time.
> Seriously consider using a fuel resistant slosh liner in the tank.
> Not doing so risks catalysing the additives, and contamination of the
> fuel. When we spoke to the Jabiru tech guys at the factory (who, I
> must say, were extremely helpful), they were surprised that our tank
> was not lined at the factory, as all fibreglass tanks leaving the
> Jabiru factory have such a lining already in place.
> Or, as the BP guy said, use a metal tank instead ;)
> Hope this information fills in the blanks.
> Cheers,
> Scott
> (Grinz. Sorry to the Kiwi's out there. Couldn't help myself ;)
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