Removing old gas

[mfoxdm16]

I bought a 9.9 Merc OB motor, and they owner used it twice two years ago, and hasn't used it since. He said there's probably old gas in the line/carb. How do I remove it? I've read that you should start the engine until it stops by itself, but is it ok to even do that with gas that old in it?

 

[Quicksilver]

Hook up the tank line, tip the motor all the way up and pump the ball the old gas will be pushed out of the lines/carb. Tip back down and run normally.