I have a portable generator I got as a result of Opal when I lived on the FL panhandle. Mine has sat for extended period of times as well. Best thing(s) to do is make sure the kill switch (if it has one) is off, or disconnect the spark plug wire, then pull the rope several times to lube things up again, drain the old gas, put some fresh gas (just a little bit to warm the engine up and put some stabil or other gas stabilizer in this warm up amount) and start it up to warm it up for a few minutes, you can let it run out of gas if desired, then drain the old oil, and put new in. If you don't many hours on it, no need to change the fuel filter unless it is clogged up. Check the plug but its probably ok as well. I put stabil,etc., in the warm up gas as you never really empty the carb/fuel lines completely, so this helps in these areas, You can start it back up and let it run some more but I usually just pull the rope a few times to circulate the oil good and put it back in the corner for a while.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.