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Sorry I haven't been around much lately. I haven't been out much on the bike and therefore nothing has happened to the bike. It is about that time to send the carb off to Ron and to get a new pipe so that I am good to go next season.

Anyway, a question came up at work today and outside of some analytical testing, I didn't know the answer. A friend has 5 cans of gas in his garage, one of which has been mixed 50:1 with oil for his 2 smoker outboard motor. He doesn't know which one is the mixed can, and which ones aren't. How do you tell?

One suggestion was to put a piece of paper in the gas cans and let it dry. The ones with pure gas will evaporate leaving nothing behind and the mixed can will leave residue on the paper.

Can't use colr of the mixture as the oild mix had no dye in it.

Mark W

One way that I can somtimes tell is that if you put the gas cans in the sun the one with oil mixed in will build up a lot more pressure much faster than the cans without.

Why would the one mixed with oil build pressure faster? I would have assumed just the opposite, since oil is less volatile than gas.

I think the residue test would be good - but then again it is not one of my bikes that may burn down due to lack of oil.

With my mindset I would likely mix the two five gallon containers and then pour it into my truck. Then purchase new gas and mix up some premix for the bike - but that is just me.

IdahoCharley wrote:Why would the one mixed with oil build pressure faster? I would have assumed just the opposite, since oil is less volatile than gas.

I have no clue why but I have observed that when I have a tank with premix in it sitin out in the sun it puffs out like a marshmallow much more than a tank without oil. Who knows I'm probably just crazy

I would put a small amount into a jar and stick it in the sun. The oil should settle to the bottom as the fuel evaporates away. I had some in a jar a while back and all that remained after a few days in the shed was the oil. Just a thought. Your idea is pretty good...

Put some of the fuel from each can on a paper towel and leave set for a few minutes. The gas will dry and leave an oil spot from the sample that has gas in it. Mark your dab of gas from each can on the towel so you can identify which can the dab is from. The blue paper shop towels from an auto parts store works great. I do this often to determine if oil is already premixed with gas.

Well I think you should round up some buddies with 2 strokers, so that you have 5 all together

Give 'em all a can of gas, and the way you figure it out, my guess would be who's ever bike didn't blow up!

Simple

Kind of like the old joke, "What's the difference between an anal and oral thermometer?"
"The taste."

I like the paper towel test so far.
I wonder if you can feel the difference between straigt and premix?

I have noticed the oil/gas color has a blue tint to it. Look with a flashlight

I bet someone sells a refractometer that can not only distinguish if there is an impurity disolved within gasoline but also determine the concentration .

*EDITTED*

Green Hornet wrote:I have noticed the oil/gas color has a blue tint to it. Look with a flashlight

Mark W wrote:
Can't use color of the mixture as the old mix had no dye in it.

Mark W

I didnt know that a refractometer works based on colours, I thought it is based on the principal that the speed that light travels through a medium is slowed down as the density increases. Therefore, if it were calibrated for regular gasoline the refractometer should be able to determine the concentration based on the density of the mixed gas. The density change would give you its refractive index. I am not positive though, any reasons why it wouldnt work?

KDX220PHIL wrote:I didnt know that a refractometer works based on colours, I thought it is based on the principal that the speed that light travels through a medium is slowed down as the density increases. Therefore, if it were calibrated for regular gasoline the refractometer should be able to determine the concentration based on the density of the mixed gas. The density change would give you its refractive index. I am not positive though, any reasons why it wouldnt work?

I believe ya mate, honest !!!

My comment was directed at Green Hornets reply.

Oh, sorry MAN! I get it now.

Here's my non Obsidian induced answer:

Run some from each can through your lawn mower

Should be able to smell it and it won't hurt the mower, hell I run all my old 2smoke gas in my mower

Hey, just my observation

Taste it... or burn it.

Indawoods wrote:Taste it... or burn it.

Now, theres an IDEA
Just cleans your palet before each taste

sorry..ot...but mr wibbens, just now looked at your avatar

skipro3 wrote: I do this often to determine if oil is already premixed with gas.

Skip,

"Often"???

I can see some remote possiblity of doing it once (putting straight gas is a pretty big no-no) but marking the container temporarliy or permanantly is not difficult.

I am fairly incompetent (at times), but I try and hide it.