Up until now the most powerful engine offered by Yamaha Outboards was the V-8 F425 XTO Offshore, but the power has now been boosted to 450 horses. Better yet, the new F450 has a number of additional features that make it one of the hottest new engines hitting the water.
Yamaha F450 XTO Offshore Outboard Design
The core design of the XTO Offshore model remains the same: this is still a 5.6-liter V-8 powerhead, featuring dual overhead cams and four valves per cylinder. Bore and stroke are 96mm x 96mm, and the compression ratio is at the high end, at 12:1. Critically, this is a direct-injection engine. Fuel is injected directly into the combustion chamber at very high pressure, hitting 2,900 psi at the nozzle. This atomizes the fuel and results in more complete burning, lower emissions, and the ability to match fuel delivery with engine load. The F425 was the first four-stroke DFI outboard, and today the F450 remains the one and only.
So, how did Yamaha wring 25 additional horses out of the same platform? All too often, we see beefed-up horsepower ratings that are the result of nothing more than computer mapping and increased wide-open throttle ranges, but that’s not the case here. Yamaha gained the extra power by in essence helping the engine breathe better. Changes in the intake and exhaust design, cams, and valves did the trick to get the air and exhaust flow increased, without otherwise changing the engine’s footprint.
Enhancements to the Yamaha F450 XTO Offshore
That’s a nice tweak, but it’s not the most significant change in this engine. That honor goes to a new charging regime. The F450 XTO has a phased angle control charging system that can produce 96 net amps. Not just at cruise, but even when at idle. By putting out so much juice this engine can power big energy consumers like air conditioning and gyroscopic stabilization systems from the moment you turn the key. And the output is “stackable,” so boats with multiple engines reap the full benefit — with twins you get 192 amps, triples deliver 288 amps, and so on. This is so much juice that it’s now realistic to eliminate the generator on many boats, without giving up the big appliances they usually feed.
Many of the F450s will naturally go onto relatively large boats and often in multiple-engine configurations, which means the Helm Master system will also come into play. New for 2023, Helm Master now adds integrated bow thruster control and a DEC binnacle with a start/stop switch located on the binnacle itself, so you no longer need to mount a separate on/off switch panel.
Another new feature worth noting is “Total Tilt.” Introduced on this motor and also now available on many of Yamaha’s new models in their lineup, Total Tilt takes the engine all the way up or all the way down if you give the tilt switch a double-tap.
Additional Highlights on the F450 XTO Offshore
Along with these upgrades and improvements the F450 XTO Offshore has a number of highlights any boater would appreciate. It features an in-water gear lube change system, so you don’t have to pull the boat out onto dry land to perform an oil change. Steering is all-electric, making hydraulic issues a thing of the past. At low rpm exhaust is diverted away from the prop for enhanced slow-speed handling. And a rotary cooling fan is integrated into the flywheel.
Is the F450 XTO Offshore the most advanced outboard on the water today? That may be a debatable question, but many people would argue that the answer is yes. And no matter what side of that argument you may fall on, one thing isn’t debatable at all: the F450 is Yamaha’s newest, hottest, most powerful outboard to hit the water yet.
For more information on outboard engines, see Best Outboard Motors 2023: The Ultimate Guide.