Hi Harry,
The sequence of events you relate do not, at least to me, support a decision to abandon use of a more economical fuel that your engine was happy with "...for many years".
If I understand correctly, your "problem" came about some time AFTER you were letting your "...airplane sit many weeks between flights". You had NOT yet ceased to use unleaded auto fuel.
Out of all the years and many, many gallons of auto fuel you must have purchased, you were able to "catch" the "jet fuel smell" in your contaminated purchase. I'm impressed!
You took a sample and sent it to Amoco, who told you not to use it in an airplane. I refer you to Univair Service Bulletin No. 28 of Oct. 12, 1987, which "...recommends that only 80/87 octane aviation gasoline be used in Ercoupe aircraft." This was probably Univair's legal department's way of saying "If and when 80/87 is no longer available, park your Ercoupe and fly something else. We don't want the added liability of having these aircraft in operation on fuels we do not sell or otherwise control."
These "expert opinions" are NOT unbiased, so I ignore them (as we all now must).
Many carry a chamois to use as a strainer in a emergency when purchasing fuel (in Mexico or other areas of questionable quality control). The condition (or maybe the presence) of the gas station pump filters where you bought this fuel would seem highly suspect if algae was passing through. Algae would muck up auto fuel filters big time!
Your transfer of suspect fuel into your coupe's fuel tanks was the decision that allowed a small problem to grow into a big one. I don't believe algae can live, much less thrive, in gasoline. This should mean that no algae could attach itself to an inside tank surface above the water level. If this was a significant area, it would suggest that for "many weeks" your tanks were NOT (1) kept full to minimize condensation and/or (2) periodically drained to minimize any water that was in your tanks (recommended practice from ground school regardless of fuel used).
Was the plane outside? If so, how much did it rain? How good were your cap gaskets? How many tank caps had gauge wires rain can follow into the tank? What were the temperature extremes? Was this a period of unusual humidity? There may have been many contributing factors to this mess.
One experience with contamination should not make you quit using auto gas. If you had a diesel truck and didn't run it often enough to avoid fuel algae, you would face similar choices.
1. You could buy your diesel fuel from another source.
2. You could drive the truck more so the fuel stays "fresher".
3. You could treat the fuel to fight the algae problem.
4. You could replace the diesel truck with a gasoline powered one.
You would most likely NOT quit using a fuel you personally know from personal experience to be proper and safe!
If you fill your coupe's tanks at a time when an FBO is being replenished from a tanker truck, the muck in the bottom of all storage tanks gets disturbed. The possibility of "contaminated" avgas is higher at such times. Contamination is not a problem unique to auto fuel.
Regards,
WRB
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On Nov 1, 2004, at 4:09 PM, [EMAIL PROTECTED] wrote:
I successfully used unleaded auto fuel for many years....from the first time EAA got approval until I had to let the airplane sit many weeks between flights.
Then I had a problem develop.
As you probably know Jet fuel has an algae additive to kill algae contamination...as agae likes to eat and reproduce in jet fuel (also disel fuels, I think).
I was using a first grade unleaded fuel to refuel instead of 100ll. Once, when I filled my container, it had a jet fuel smell....I thought well, no problem...... BUT WAS I WRONG.!!
Gasoline is transferrred from the refineries by pipeline, one grade of fuel, proceeded by another grade, etc. The interface is removed out of the supply line at the recieving station and re-refined by local units... to keep the slugs of different fuels pure....
Evidently I got a slug of contaminated fuel..
In just a few weeks, I began to get a green water mix when I drained the sumps, and realized I must have an algae contamination... I sent a sample to the manufacturer (Amoco) for testing.
They advised, yes it looks like aglae, but we do not recommend our fuel to used in Aircraft,...sorry....
I later realized that LEAD additive in fuels must kill algae; and also that now the fuel industry adds algicide at the refinery in jet fuels....as opposed to several years ago when the algacide was added at the refueling station.
I drained all my tanks, added algicide additives, redrained, etc...and finally got no more Green Stuff when draining the sumps...BUT, later to find there was considerable Black goo still in the tanks..( dead Algae ?)...and required removal and cleaning of all tanks...
Now , even tho I am aware that auto gas is approved ( and I successfully used it for over 10 years or so), I now only use 100 ll.
Yes, I wish 80 Octane was now available...AND PERHAPS A MIXTURE OF 100LL AND AUTO FUEL MIGHT BE THE ANSWER...but, IT IS A DRAG TO HAVE TO LUG IN AUTO FUEL AND MIX WITH 100 ll FROM THE FBO.
73 Octane was probably an unleaded fuel, but I am not sure. I do remember being able to purchase "white Gas" at the local ESSO station in the early 1940s....this was probably the fuel with which the C-65/75/85 engines were certified.
I understand that Lead was first used in the late 30's as we prepared for war with higher HP engines that needed the anti -Knock additive of Tetra Ethyl Lead/ developed by the Ethyl Corporation.
REgards,
Harry Francis
Elliston, VA
N-93530
