Really, that's over $200 worth of fuel. Try it in something before you throw it out. I gave the local rc club 6 gallons of 60% boat fuel that was 15 years old, stored like yours was in a dark basement, and they ran it. It ran fine. A couple guys had 1/8 hydros and that much free fuel was a godsend. You'll know more and can make a better decision after the run test. Like Mark said maybe not in your best engine but try it before throwing it out.