Filling a gap in Yamaha's outboard range
Yamaha's new outboard engine, a 350 hp V6, fills the gap in the Japanese motor manufacturer's range between its 300 hp V6 and 400 hp V8 XTO. Although the new engine is based on the existing V6 block, fundamental modifications have been made to gain the missing 50 hp, starting with an increase in displacement. From 4.2 to 4.3 liters. Added to this is work on all the parts to extract maximum power from the engine, and be able to transmit it. Intake and exhaust valves have been enlarged, and a throttle valve larger than that of the 300 hp and borrowed from the XTO V8. The new crankshaft, with a longer stroke, delivers more torque, while the baseplate is reinforced to transmit power. Top-of-the-range iridium spark plugs complete the improvements. In this way, the 350 hp becomes more than just an evolution of the existing V6.
Featherweight and more load capacity
By using its V6 base, Yamaha is able to offer the lightest 350 hp on the market, at 293 kilos, when the other 3 major engine manufacturers exceed 300 kilos, and even 350 for some. In addition to this power-to-weight ratio, the engine manufacturer also boasts a high electrical charging capacity. Thanks to a ventilation system for the engine head and alternators, nearly 10 amps of current have been gained.
Adapted boat configurations
We were able to discover this 350 hp V6 on board various Yamaha-equipped boats, during tests off the coast of La Spezia. From a triple-engined Invictus 420 with a total output of 1,050 hp and a displacement of 11,400 kg, to a single-engine 350 hp Yamarin 80 DC weighing 2,200 kg, to a twin-engined Sterk 31 RC weighing 2,620 kg, there was a wide range of configurations, allowing us to see the full potential of this engine, which reaches maximum power at a rather rapid 6,000 rpm.
If the relatively high-pitched noise of the engines at high speed could sometimes prove annoying on the units whose hard-top reflected the sound, these also being the heaviest units, whether a 42-foot Invictus or a Leader 10.5 CC, the engines remained relatively discreet at cruising speed, and even launched at full speed on the lighter boats, the Sterk reaching 60 knots. Whether maneuvering in port with the joystick or making fast offshore turns, the right choice of propeller enabled the engine to deliver the torque and maneuverability the boat needed.
With its well-positioned power-to-weight ratio, the new 350 hp V6 is above all a lightweight solution for gaining a few knots on boats with moderate displacement, but will also be able to offer heavier boats an outboard configuration without switching to V8 or V10 engines.
Available from August 2024, Yamaha's 350hp V6 F350NSA is priced in 2024 at ?42,350 incl. VAT with X-shaft and ?42,690 incl. VAT with U-shaft.
