You were smart. You invested in a portable backup generator... and it's a good thing because you lived without power for an extended period. Now that you have power back, what should you do with your portable backup generator so that it's ready to go next time you need it?
The biggest problem with storing a portable backup generator is neglect between uses. The power comes on and the generator is forgotten. There are several steps to take so that your portable backup generator is truly ready for its next use. According to Jon Hoch, founder of ElectricGeneratorsDirect.com it all come downs to keeping the engine clean and the fuel fresh.
The first thing to do is to run the engine dry. Most new portable generators  feature a fuel shut-off valve. If you close the valve, you will stop flow of gas from the tank to the engine. Fire up the engine and run it until it dies to ensure that all of the gas in the engine is used up. This will prevent the carbeurator from gumming up with old fuel.
If you cannot run the engine dry, the next best option is to occasionally start your engine and let it burn off the old fuel in the carburetor. In either case, you should add fuel stabilizer to the tank.
You should also change the oil if you have been using the generator for an extended period. Your generator's owners manual will have step-by-step instructions on performing an oil change. You may want to check and change the spark plug if needed. The spark plug has to stay dry in order for the generator to be able to run. You should store the generator with a cover to protect it from dust and moisture.
To have it ready to use next time, keep a supply of gas on hand. The best bet is to plan on 48 hours worth of fuel. Consult the owners manual for the size of your generator's tank and how long that amount of fuel will run it. The gas should be stored in proper gasoline containers and be well-labeled. Store them safely in a garage or shed.
If you follow the step to store your portable backup generator safely, it will always be ready whenever you need it.