"When Good Gas Goes Bad"-Part II

[Mek-a-nik]

I started this on the other forum: http://www.perr.com/phpBB3/viewtopic.ph ... s+goes+bad
It's been about 13 months so far. I just realized that other than re-testing for water content with a B&S ethanol tester, I can't really tell much. They all look and smell about the same. The untreated sample may smell a little funny, but I'd have to do a blind-folded "sniff" test to know for sure.
I'll check the water content, and then wait another year and test again, when most of the products effectiveness should be wearing off.

[bgsengine]

One point I didn't make on the other forum - the sample *size* can make a difference - so I wonder how big ARE your samples?

[Mek-a-nik]

Not very big. Maybe a few ounces each.

[bgsengine]

OK yeah - that is one factor that may make the difference between a "test" and "real world" - The surface area of the headspace above the samples -

less surface area = less air to interact with or carry moisture.

a 3 ounce sample in a dish will go bad far more quickly than the same 3 ounce sample in a vial - with or without covers/lids - So, any testing needs to have those "caveats" noted as well..

Ideally a true test would be to purchase a dozen 1 gallon gas cans, and fill them with exactly 1 gallon each (BY WEIGHT, down to the ounce, not by volume - that way you can also weight later them to check the rate of evaporation!) , then add in your "test" parameters to each. but, obviously, with the price of gas cans these days probably not exactly a feasible test unless you have a bunch of cash you can afford to throw away like that..

Of course, if you have some suitable sealed containers that won't be affected by the gas or additives, those could work as well..

can you tell the thought to run some tests just like that have crossed my mind before? LOL!

[JandL]

What are your thoughts on a kit to test ethanol content? I see the one from Briggs and a few others, which do you recommend?

[bgsengine]

easy enough to make your own if you have any suitable graduated cylinder , say 10ml in 1ml major increments and smaller 0.1ml scale, fill to 1ml of water and 9ml of gas, shake it up, let it sit a while and then using the markings , you can determine the % of alcohol content measured by the increase in water level, caused by the ethanol mixing with the gas - those simple testers work based on the tendency of ethanol to phase separate when enough moisture is introduced. (phase separation happens at as small as 1/2 of 1% water absorption)

most ethanol content tests involve the same principle - but there are some kits such as the one from B3C that takes it further, and is actually able to measure the *amount* of bound water that has already been absorbed into any given fuel sample.. not just how much ethanol is in the fuel.