Definitely not enough time. It will take you at least one hour to get to the ferry terminal, another one hour to wait in line, clear security and board, 30 minutes on the ferry to the Statue, at least one hour at the Statue, 45 minutes on the ferry back to lower Manhattan (stops at Ellis Island on the way back), at least another hour back to JFK. That's over five hours not including the two hours in advance you need to be back at the airport for check-in/security. Sorry to disappoint you!
Definitely not enough time.