At about 1220 eastern time, a Cessna 402B ditched in the Atlantic Ocean approximately 10 miles from Marathon Airport. The pilot sustained minor injuries. The pilot was returning to Tamiami Airport from Havana, Cuba, on a Part 135 flight when he detected a strong smell of fuel in the cabin. The airplane instruments did not indicate a problem, but a few minutes later he smelled burning and noticed a small fire on top of the right engine cowling. He secured the engine. The smell of fuel worsened and the left engine started missing and sputtering and he ditched the airplane. He was rescued by a boat after being in the water for about 20 minutes.