Lawnmoving gas can question...
...because I don't know who to ask! HOW does one get to be 47 without EVER having mowed a lawn? I bought a lawnmower and I used it. Yes, I remembered the oil and I got it started fairly easily too. I didn't do too badly either. Just never had a reason to mow before.
My question is about the gas can. It is plastic and has a place to pour gas and then this screw cap at the back end of it. I am thinking...you don't leave the gas open to evaporate because well that is not too smart or environmentally right. If you seal up both the spout (which I did) AND the small hole with the screw cap, you then are building up vapors with the summer heat, right? So do you screw the cap on that little valve or do you leave it open or what? At over $3 a gallon I don't want it to all escape you know?
Help the elderly unskilled lawnmowing wannabe!
Close it all up. The heat of the summer is not going to cause the gas to explode. A spark will.
Keep your gas can in a shed or the garage and out of sunlight. You don't want rainwater to leak in and contaminate the gas. Also, too hot temperature will cause gas quality to deteriorate.
The only time you want to open it and leave it open is if you have old gas you're trying to get rid of and you want it to evaporate. Actually better than pouring old gas down the drain and having it go into wastewater runoff. Although, I believe there are some gas stations that recycle old gas.
http://www.mapllc.com/safety/api_gasoline_safety.html
I think that little opening in the back is to make it easier to pour...?
Yes. You're right. So no vacuum. Won't glug, glug.
Like Cates said, store it completely closed up, out of sunlight, away from house, don't let water get into it (this will not only dilute it, making it worthless to run things, but will allow it to freeze easily during winter), and best not to let it get to hot when stored (80 degrees Fahrenheit is recommended tops, but that's not so realistic for our sheds in summer usually ::)). Gas will lose its octane as it ages (and high temps will speed that up) and it will also get microbes and junk growing in it, gumming it up as it ages, causing it to not run your equipment right. Never store or pour gas near any ignition sources like a water heater, anything with a pilot light, spark, flames, hot or running engines, etc.
Like you mentioned LDF, as gas heats up during warmer temps during the day it will expand and release vapors, then contract during night as cools down. These vapors contain Benzene which is a known carcinogen, so it's not good for anyone to ever breathe. If you store you can closed up like suggested, just make sure you do not fill the container full so there is room for the expansion of vapors. For example, if you have a 5 gallon can, maybe only fill it to 4 gallons. When you go to pour the gas on warner days, make sure you open the little vapor release cap first to release the pressure. Otherwise the pressure (and gas) may blow out onto you from the big cap if you open it first. If you get a can that doesn't have a smaller vapor release (the new ones made of plastic are designed to be more flexible and allow for expansion and contraction-- just a pain to pour IMO) then just make sure you undo the cap slowly to allow for the pressure to release slowly.
And if you need to get rid of bad gas, NEVER just toss in trash or dump out. It will get into our land and water and it's a hazardous material and toxic. You can call your local fire department and ask where to dispose of, and most cities will have a hazardous materials disposal site and accept that stuff from citizens on certain days, etc. Not a good idea to let it evaporate out of your can either if trying to get rid of. Again- bad for anything to breathe those vapors, and gas vapors are heavier than air and will not just float up and away and disperse into the air.
Sorry for the long post. :o Hope it helps!