Lightest in class, with plenty of low-down grunt, Yamaha have not missed a trick with this engine.   

Not that Yamaha gave any hints about a new member of the ‘350 club’, but this motor is no surprise. Given that they were the first into this arena back in 2007 with their big 5.3L V8 F350, a development of the V6 F300 launched in 2010 has always seemed a distinct possibility.

Yamaha F350 V6

The F300 is an impressive engine, which, weighing 260kg 14 years ago, set a standard for power-to-weight ratio, only surpassed by the V8 Mercury Verado range in recent years. This new 350hp V6 certainly appears to be based on the same 60-degree F300 V6 engine block, but with some subtle, though also substantial, changes. The F350 has been ‘stroked’, meaning the 96mm-cylinder bore remains the same as the F300, but the stroke has been raised from 96mm to 98mm. This results in a meagre capacity increase from 4169cc to 4256cc, but the real benefit is in the rise in torque that a longer stroke provides. There have also been quite a few other developments, notably a new ‘robust crankshaft’ to handle the extra low-down power.

Yamaha F350 V6 - The TERE system pushes the exhaust out forward.

The TERE system pushes the exhaust out forward.

However, like all engine evolution programmes, the icing on the cake is in the head. This engine has larger intake and exhaust valves to maximise intake/exhaust flow, and it ‘expertly manages air displacement’ using tailored intake manifolds equipped with 40% larger surge tanks to maximise the amount and timing of air drawn into the intake ports – while also ensuring even distribution to each cylinder. Better airflow equates to more horsepower, especially with a newly developed fuelling and ignition timing map, and an 11:1 compression ratio. Yamaha have developed new fuel injection control technology for the F350, which produces a longer injector duration than the F300. Also, the cooling system has been enlarged to cater for the extra power delivery. Yamaha now incorporate the use of iridium spark plugs – appreciated for their durability and powerful, efficient spark. The end result of this ‘head work’ is that horsepower, torque and fuel efficiency are all enhanced.

Yamaha F350 V6 - The F350 can trim fully clear of the water at the press of a button.

The F350 can trim fully clear of the water at the press of a button.

The F350 at 293kg (lightest form) has put on 33kg of weight over the F300, but, as is rightly claimed, it is the lightest in its class. It is fair to say that this is not really a result of internal engine changes, but one aspect is evident, and that is that the oil capacity has increased from 6.6L to 7.9L, so there should be a bigger sump. However, to deal with the extra torque, Yamaha have developed an uprated bevel gear in the bottom section of the outboard leg, and with this it is likely that the leg itself has been ‘beefed up’. There is also a feature called ‘Thrust Enhancing Reverse Exhaust’ (TERE), which routes the exhaust forward through an outlet above the prop, rather than aft. This is claimed to improve the efficiency of the propeller when the engine is in reverse, as the exhaust will not disturb the water behind the boat. Like most of Yamaha’s outboards, the F350 has the fast-acting built-in Digital Electronic Steering (DES) system, keeping the rigging neat and minimalistic.

Yamaha F350 V6 - A new enhanced bevel gear for the F350.

A new enhanced bevel gear for the F350.

Price: From £35,500 (inc. VAT)

Helm Master EX

Yamaha’s Helm Master EX boat control system has been enhanced to add further ‘ease-of-use’ benefits to the Yamaha outboard range. An industry first is the newly launched single-engine joystick berthing. Helm Master obviously has the benefits of fast-acting DES, which, working with new ‘state-of-the-art’ software, enables the Helm Master joystick to vector one single engine for slow-speed manoeuvring. With just one engine, this system will no doubt have limitations as to just how reactive its boat-controlling skills are. However, it will be able to vector the outboard, while selecting forward and reverse as needed more quickly than a human, and be more seamless in the process. There is another factor to fit into this equation, and that is that Yamaha have now paired up with both Sleipner and Vetus, providing variable-speed bow thrusters for the Helm Master system. This will make single-engine joystick berthing faster and more reactive, and the argument is, of course, that if you have a bow thruster, why do you need a joystick? The answer is: why not if it makes life easier, which it certainly will do with a strong tide running.

Yamaha F350 V6

Helm Master is also now available for craft with up to five engines, and you can have an additional two extra remote joysticks for locations like the flybridge. Yamaha’s Drive-by-Wire 6×9 top-mount control box has now been completely redesigned for better ergonomics, and with new enhanced features like Speed Control and Neutral Hold – the latter locking the engine in neutral when needed. There is also a new slim side-mount control, again with improved ergonomics, which is ideal for boats with limited space at the helm.

Helm Master also has the optional benefit of Yamaha’s easy-to-use autopilot system. It requires the fitment of a small control panel at the helm, and a heading sensor fitted within the console, plus a GPS antenna and a control unit. It provides various features, notably Course Hold, where you can fine-tune in increments from one to five degrees to keep on course. It also has Heading Hold, which will keep the boat heading in the direction of the compass reading. For longer passages or where accurate pilotage is needed, Track Point comes into its own, enabling you to simply tap out a course on a touch screen MFD, and then have the boat follow it. Finally, Stay Point is an aspect of Helm Master that few will fail to use on a regular basis. It is in effect a hold-station facility, which, when engaged, holds the boat on location while maintaining its heading – ideal when waiting for a fuel pontoon to clear or a lock to open.

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