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Yamaha rolls out the big guns

THE world’s largest outboard manufacturer, Yamaha, this week unveiled its “Next Generation” offshore four-stroke engines on Queensland’s Gold Coast.

Based on a 60 degree V6 configured engine with the biggest displacement in its class – 4.2 litres or 254 cubic inches (anyone remember Holden’s 253c.i V8?) – the Offshore V6 Series F300B, F250D and F225F are aimed squarely at larger boats in the trailerboat sector and supersede Yamaha’s previous offerings in this power class, including its F300 V8. The company’s flagship F350 V8 will remain in production.

Yamaha has upped the ante in this competitive sector of the market and started from scratch with a completely new, albeit bigger, engine. The predecessor was based on a 3.6 litre block. The manufacturer has achieved substantial weight savings over preceding models, (253kg for 25” shaft models, 259kg 30” models); most notably the V6 F300B weighs 112kg less than the V8 F300, while 23kg has been trimmed from the 225 and 250 models.

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The V6 outboards also feature many tried and proven technologies seen on other Yamaha outboards and design innovation learnt from Yamaha’s involvement with high performance cars to achieve the desired engine capacity. A sleeveless cylinder facilitates the use of enlarged bores and hence delivers increased capacity for a lesser increase in overall dimension. The surface of the engine’s cylinders too have undergone a plasma fusing process that, according to Yamaha, ultimately delivers a cylinder wall that is 60 per cent harder than steel.

Being state-of-the-art, the engines typically feature four valves per cylinder, double overhead camshafts, multipoint electronic fuel injection (one injector per cylinder) and variable camshaft timing (VCT) all controlled via the engine’s ECM or “brain”. Yamaha has improved the “breathability” of these engines for better performance via its Tuned Long Track intake manifold and In-Bank exhaust system – the latter used on Formula 1 race cars and in this case helping reduce engine size. As a result, up to 14 per cent more intake mixture finds its way into the combustion chambers and 10 per cent more exhaust is expelled than predecessor models.

Tech heads are also sure to be excited by other innovations seen on these engines such as TCI direct coil in cap ignition, which basically does away with potentially troublesome ignition leads and a new 70amp high output alternator ensures 50 amps of net charge goes to the primary cranking battery in dual or multiple installations.

Of note is Yamaha’s new electronic rigging system that incorporates a cool looking 5” multi-engine LCD instrument display – that can be set up to show levels in up to four separate fuel and or water tanks – and push button start/stop panels. An optional Y-COP immobiliser system that disables the engine’s ignition system via a car-like transmitter can also be integrated.

The Offshore Series sports a 1.75:1 gear ratio, and a shift damper system (SDS) designed to greatly reduce any clunkiness when shifting gears.

Yamaha Australia’s head of marine training, Dan Power, told the conference anyone who thought two-stroke outboard performance could not be achieved with a four-stroke would change their mind after seeing the Offshore Series motors in action.

Fisho got a chance to see if the new Yamaha big bangers lived up to this claim, with a number of the engines fitted to suitable craft available for test runs. First off the rank was a Yellowfin 6700 cabin plate boat fitted with a whisper quiet at idle F225F. If we’d wondered why Yamaha’s Kiwi driver Hugh was so chipper as three of us jumped on board we didn’t for long. After getting out into the Broadwater channel he checked we were holding on before slamming the “clunk-free” shifter forward. The response was instantaneous: the engine growled, the Yellowfin shot forward and sea and land went by, fast. Was this really a four-stroke? It was, apparently, and delivered an impressive introduction for more of the same on water fun.

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From there it was a bit of a blur as we tried six different boats fitted with the Next Generation donks. A highlight came with my turn on the wheel of a Bar Crusher 760 HT, fitted with an F250D. Having reviewed one of these impressive boats in Melbourne a couple of years ago – fitted with a competitor’s four-stroke – I was interested in how the Yamaha would perform on its transom. Checking notes taken after the drive pretty much say it all: “Brilliant acceleration, especially from 3500rpm on…”

The new 250 pushed the 1200kg (dry) Bar Crusher hull along impressively from the get-go thanks to its very torquey and responsive engine. And the muffled growl emitted when approaching full noise would gladden the heart of boy racers everywhere… For the record the boat hit just over 40 knots (75km/h) at around 5500rpm (WOT). And like all three engines sampled on the day, the 250 at mid range revs seemed to effortlessly move the boat along at a good pace while achieving impressive economy. At 3000rpm the boat was doing a tad over 18 knots using an average of 23 Lph of fuel or travelling a distance of 1.4 kms per litre of unleaded fuel used. On the latter, Dan Power says Yamaha doesn’t dissuade users of these engines from running them on ethanol based fuels, provided the ethanol component doesn’t exceed 10 per cent.

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After a taste of the F250D, the F300B was eagerly awaited. It came via an impressively riding Cruise Craft 685 Explorer that appeared to offer the complete package for anyone with offshore fishing ambition.

Dual F250Ds installed on a Noosa Cat demonstrated the effectiveness of having a very responsive 500hp on tap when going forward in a confused sea – the like of the entrance to the Gold Coast’s Seaway as we saw it on a fairly lumpy day.

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The standout impressions of the Offshore V6 came of its very smooth transition into gear, with only some clunkiness noted when shifting into reverse. Any banging as the gearbox shifts into forward appears to be a thing of the past with these motors, thanks to the effectiveness of the SDS. But overall it seemed that pure performance drew the biggest reaction.

The overall consensus amongst the assembled boating media after sampling Yamaha’s new big guns seemed to be that the engines had lived up to the manufacturer’s claims.

Anyone in the market for a new outboard to power an offshore boat should give these consideration. While there really is no substitute for cubic inches when it comes to performance, Yamaha looks to have delivered plenty of grunt while throwing impressive fuel economy into the bargain. Another boating writer on board the Yellowfin as we cruised along at midrange revs remarked that the F225F was using about as much fuel as his carburettor two-stroke 50hp outboard.

The Offshore V6 Series outboards are available through Yamaha dealers now.

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