yes
YES.
Shock first, then check your stabilizer. Add stabilizer as needed.
yes, if fuel is going to sit for extended periods you need to add fuel stabilizer to it
Add fuel stabilizer to your gas tank to allow for easy starting after storage.
Fuel will last only about a month (even that's pushing it) add a bottle of fuel stabilizer (available at your local hardware store) and the fuel will be good for "almost ever"
winterizing a lawnmower is easy. 1: drain all of the fuel from the gas tank, and run the mower until all of the fuel is out of the lines and it stops. if you want to avoid all this, you can simply add fuel stabilizer. 2: drain and clean the floatbowl ( if equipped)
Add chlorine and stabilizer.
Every year you should change the oil, grease all the joints, and add fuel stabilizer before you store it for the winter.
Have the coolant tested to be sure it will protect from freezing to at least -34 degrees F. Add a fuel stabilizer to the fuel tank and fill the tank with fuel. Run the engine to get the stabilizer throughout the system. Once parked remove the battery and store the battery in a safe place to keep from freezing. Perform a trickle charge on the battery once a month.
It is hard to give a definite answer because it depends on how you store it. Assuming the gas was fresh when you bought it, you store it in a cool place, in a sealed container with the container full, and you use no fuel stabilizer, it will stay usable for about 2 months. If you add a fuel stabilizer it will stay usable for about 12 months. Do not use any fuel stored for over 12 months as it will contain some sludge which can clog injectors and carburetors.
Nothing except possibly a fuel stabilizer if you're going to store the vehicle. You may also want to add a good fuel injector cleaner such as Seafoam or Techron once a year.
Stabilizer can effect the pH some but usually it is a very minor amount. You should be able to swim the same day.