gas question

I was not able to take the boat fishing last year; therefore, I've got about 65 gallons of fuel on the boat that's been sitting for about a year and a half. Whenever I re-fuel, I always mix the higher amount of Sta-Bil Marine. My question is this: Is it OK to run the boat with this fuel or should I figure a way to, somehow, dispose of the fuel? Thanks for the help.