Mercury verado 350

Mercury’s new supercharged, in-line six-cylinder Verado 350, which debuted in February, is now the most powerful outboard in its model family. Mercury says the 350, which operates on 89-octane gas (though 91 octane is recommended for full performance), provides up to 10 percent greater fuel economy than competitors. At 668 pounds, this Verado weighs 95 pounds less than the nearest four-stroke competitor, the company says. The 350 features a cold-air-intake system designed to collect air from outside the cowl and deliver it to the supercharger. Other attributes include the top cowl’s labyrinth design that keeps the powerhead dry, and a styled vented flywheel cover that facilitates engine-heat dissipation. The Verado 350, which comes in Phantom Black, Cold Fusion White or Warm Fusion White

 

The Yamaha F350 runs fine on 89 octane. It's a V8 and does weigh 763 lbs for the 25" shaft. http://yamahaoutboards.com/outboards/V8-5_3L/specifications