----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----
Tim & all,
Based on my personal experience in the 80's we should take Harry's
experiences seriously, although I suppose it's possible that unleaded auto fuel
formulations may have changed since the 80's to minimize the algae or
'green slime' problem.
I had not considered this until reading the earlier posts
however, in the past algae in unleaded auto fuel was a very real
problem if it sat for long periods.
I worked in a motorcycle shop on the early 80's where there was
a large over supply of new motorcycles, resulting in many new
motorcycles sitting crated in warehouses for months or even several years.
Almost every new unit sold after prolonged storage had the
then dreaded and obnoxious 'Green slime' contamination throughout the
fuel system. Many if not most had to have the entire fuel system torn
apart and thoroughly cleaned. In some cases the carburetor jets
(usually the idle circuit) had to be replaced to get the bikes to run
properly. This was a nasty work and sometimes had to be repeated to
clear out all of the accumulated green slime
contamination.
I would guess that the new 'sealed' auto & motorcycle fuel systems may
not experience this problem however I suspect that the problem could occur in
many if not most aircraft fuel systems. Perhaps unleaded fuel
formulations have changed in the last 20 years to mitigate this issue (any
chemical & petroleum engineers out there?).
Harry, what year did you have the algae problem? Has anyone
else had similar problems in recent years using auto fuel?
It's certainly something to think about.
I have the auto fuel STC from the earlier 85 HP installation in my Ercoupe,
but it now has the O-200. I had avoided auto fuel due to my concerns about
potential alcohol & water contamination (I live in CA where auto fuels are
'oxygenated' for lower emissions), and the potential detrimental effects of the
auto fuel on some parts of fuel systems (o-rings, seals, and tank sealant or
slosh).
I'd be VERY interested to hear any information about the potential
effects of auto fuel on aircraft fuel systems (Ercoupe in particular), and
the fuel tank sealants or slosh used in aircraft fuel tanks. Does
anyone out there know if this is a valid concern?
I'll go out of my way to use 80 octane as long as it is
available. I've used 100 LL, and fouling can still be a problem even
with the fine wire Iridium plugs.
I also suspect that the extra lead in 100LL causes some problems with
sticking values, and perhaps sticking rings & cylinder scoring in
the lower compression engines? Maybe someone else knows it
this concern is real or not?? (Jan & others?)
Dan
N3968H
----- Original Message -----From: Tim and Martha BriggsSent: Sunday, January 25, 2004 9:53 AMSubject: RE: [COUPERS-FLYIN] Auto fuel STC----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----Wow - I never heard of anything "growing" in/on a fuel tank. What part of the country are you in? I'm also surprised that a "name brand" fuel like Amoco would have enough impurities to give a bad smell like that.Food for thoughtTim-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Sunday, January 25, 2004 3:38 PM
To: [EMAIL PROTECTED]; [email protected]; [email protected]
Subject: Re: [COUPERS-FLYIN] Auto fuel STCTim,I had successfully used auto fuel for many years....UNTIL I had to let the airplace sit for a while.I really cannot blame the problem on Auto Fuel as such; but also to my dismissal of a bad smell...which I ignored. The fuel from the filling station Amoco un- leaded...slightly smelled of deisel fuel. Amoco fuels generally smell very clean.I thought, no problem.But, the Coupe was then only being high speed taxied about once a week, so very little fuel was used.... As mositure accumulates in fuel tanks, I, of course always drained any moisture before every high speed taxi ..... assuring all water was removed....BUT, after several weeks of hot , high moisture weather, on draining the sumps, I got a green mess in the water. mmmmm.. Algae ????? Deisel/ jet fuel ????As most of you know, Jet fuel is now treated at the refinery with Prist or some other algacide, as algae grows in fuels like jet fuel/ deisel, etc.....to prevent Algae growth and contamination of the fuel system.I took samples and sent to Amoco.... Their response was we don't approve Auto fuel for airplanes... end of message.The transportation of fuels thru pipelines pushes one fuel type with another..... The result is a mixed section of the fuel slug. The recieving storage field takes out this slug of mixed fuel and it is re-refined. BUT, sometimes they don't get all of the mixed fuels out of the system. Generally this is not a problem, as the mixed fuel is diluted in clean fuel. BUT, I ignored the smell, and paid dearly for it.I cleaned the tanks, dosed the system with Prist, and cleaned the CArb; and put in 100 ll.I saw no more sump drained algae.....BUT, when John Wright rebuilt my Coupe, last year, on inspection of the header tank, he found gobs af algae, still in the system....So, Auto gas is not a problem, but while leaded fuel evidently kills the algae, unleaded evidently does not...especially if you get a slug of diesel/jet fuel in your tank. And once contaminated, it is very difficult to remove all algae without removing all tanks and thoroughly cleaning the entire system.If the fuel smells like jet fuel...even remotely, I would suggest you don't use it.As stingy as I am, on draining the contaminated fuel, I saved it and put it into two of my cars....Bad decision.....I lost both fuel guages in about a week.... Algae eats copper ! (that is why the algae is green) ...copper wireing in the fuel guages.......... New cars have sealed fuel systems, that do not allow water vapor into the tanks,...so no water, no algae problem.....but if you put it in the tank, foolishly...you have to suffer the consequences...I now use 100 ll, tho I do recognize the potential valve sticking problem the high levels of lead can cause in these low compression engines. After all the 65/75 & 85 were all certified on 73 octane fuel.Fly Safe - Have FunREgards,Harry FrancisN93530============================================================================== To leave this forum go to: http://ercoupers.com/lists.htm Search the archives on http://escribe.com/aviation/coupers/
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