Yellow fuel in sump

[AuntPeggy]

The C-172 has not been getting enough exercise lately. The other night, Hubby took it up for its first launch since the annual in May. The fuel tests for both wings looked normal and blue, but the one under the belly returned what looked like yellow fuel. A second sample was the same. He eventually removed about a pint of the wrong colored stuff before getting blue fuel.

Any idea what turns the fuel (100LL) yellow?

Interesting side note: He was there with an old friend who is in the habit of simply pulling the knob and discharging some fuel from the gascolator without capturing it into a jar to test. If it had been his airplane, he would not have known that it was the wrong color.

 

[Jim Logajan]

SG:

Gasoline: 0.73
Jet-a (Kerosene): 0.82

www.engineeringtoolbox.com is your friend.

Jim

Maybe. Maybe not. Just a few weeks ago I was reviewing the chapter on properties of solutions in Pauling's descriptive "Chemistry" text and he states:"Substance vary greatly in their solubilities in various solvents. There are a few general rules about solubility, which, however, apply in the main to organic compounds.

One of these rules is that a substance tends to dissolve in solvents that are chemically similar to it. For example, the hydrocarbon naphthalene, C[sub]10[/sub]H[sub]8[/sub], has a high solubility in gasoline, which is a mixture of hydrocarbons; it has a somewhat smaller solubility in ethyl alcohol, C[sub]2[/sub]H[sub]5[/sub]OH, whose molecules consist of short hydrocarbon chains with hydroxide groups attached, and a very small solubility in water, which is much different from a hydrocarbon."

 

[Jim Logajan]

There is no "maybe, maybe not" THe OP asked what the specfic gravity of two substances were and I posted them. Whether or not they are miscible is a totally different question.

And whether or not they STAY miscible over hours, days, weeks, or months is another totally different question.

Jim

Sorry, I incorrectly quoted your post when I should have quoted post 10 in my "maybe, maybe not" reply. I quoted your post only because it appeared to be the most recent in the subthread about Jet-A and 100LL mixing vs separating. Your post was of course a proper answer to the question.