When autumn rolls around, "It's that time of year again folks." Don't just shove those small, gas-powered machines into the shed and forget them. There's something you have to do first: Prepare them so they'll start next spring.
If your lawnmower or other machines you use in the summer are left with untreated fuel all winter, chances are you're going to have a tough time starting them the next time they're needed.
Just because it will be cold out doesn't mean gasoline can't go bad. There will be fluctuations in temperatures that will cause condensation to form in the fuel. The length of time it sits will also change the properties of the fuel, causing sludge to form. This can do great harm to the carburetor; sometimes with no recourse but to replace it or at the least you'll be watching your grass grow while your local small engine shop is rebuilding it.
There are several products on the market you can use to preserve fuel for several months. They all do the same thing. Just ask for a fuel preservative at a local auto parts store. Several big box stores carry them also. Just follow the instructions on the containers.
Some people prefer to empty the fuel tanks and run the engine until it quits. Either way of doing it will work, but I prefer to preserve the fuel. I've done it that way for years and it works quite well.
Doing simple things like this to your mowers, weedeaters, tillers, etc, will insure they start each spring and last for years.