Yamaha has unveiled its largest four-stroke outboard to date at its Bridgeport, Alabama, test facility. Based on a 5.6-liter V8 block with four valves per cylinder and dual overhead cams, the 425-hp XF450 was conceived from the beginning with the ever-growing big-boat market in mind.
“We started by figuring out what size and kind of propeller we wanted to drive and then started designing the outboard from the lower unit up,” said Ry Landry, a product manager for Yamaha Marine. “The big boat market has exploded over the last 10 years and this outboard is aimed directly at that market,” he added.
The XF425 features a number of industry firsts and innovations, including:
· The highest-ever compression ratio (12.2:1) in a four-stroke outboard.
· The first direct-injection system in a four-stroke outboard.
· A charging system that produces up to 90 amps, 72 of which are available at only 1,500 rpm.
· Iridium spark plugs.
· Plasma-fused, sleeveless cylinder liners.
· Up to 300 percent increased thrust in reverse compared to Yamaha’s F350 outboard, thanks to a unique exhaust system that directs exhaust gasses away from the propeller.
· A first-of-its kind integrated electronic steering system.
· A four-thermostat cooling system (two per cylinder bank) that ensures even cooling of internal components.
· A quick-connect hose bib that allows the lower unit gear lube to be changed while the boat is still in the water.
· An additional 3.25 inches of clearance when tilted fully up, compared to the F350.
The XF425 will be available in gray, pearlescent white or unpainted, for owners who want to customize. Available shaft lengths include 25-, 30- and 35-inch models. The XF450 starts at $44,000.
For more information, visit yamahaoutboards.com.
