YAMAHA'S NEW 225, 250 & 300hp 4 STROKES


Yamaha’s new V6 triple 
line-up of whopper 4-stroke 
outboards utilises significant components of next-generation 
technology to achieve the lightest motors in this category so far.

Only a few months after it presented us with a groundbreaking lightweight 70hp 
4-stroke outboard, Yamaha is at it again with an all-new series of 4.2 litre V6 225, 250 and 300hp engines.

Since being the original 300hp outboard, Yamaha was eventually left somewhat behind by virtue of its 300hp being a 5.3 litre V8 while newer 300hp competitors were V6s, and therefore lighter. Astonishingly, these new Yamaha motors are actually 20kg lighter at 255kg than Yamaha’s current 200hp model which (at the moment) retains its earlier 3.3 litre V6 powerhead, and weighs 275kg.

At 370kg, Yamaha’s V8 300 was something of a heavyweight, although it was well known for the way it could get hulls capable of handling its substantial weight moving! Which brings us to a fascinating aspect of what now appears to be the first few of a whole new generation of lightweight motors from Yamaha.

In drag racing’s good old days, there was a saying that went “there ain’t no substitute for cubes”. For generations, this was simply how it was. Bigger-capacity motors meant more power, end of story. Technology actually kicked that one into touch back in the ‘80s if you can remember the heady days of 1200hp 1.6 litre F1 engines. They achieved such monumental power outputs with the help of forced induction (turbochargers), a technology that’s proven more applicable in marine engines to inboard diesels.

What has, however, trickled down to today’s outboard motors generally are production and metal technologies developed in that era which not only allows more power to be produced by relatively small motors but means this power can be delivered with the long-term reliability we expect from outboard motors in 2010.

Yamaha’s new V6 triple line-up utilises significant components of next-generation technology to achieve the lightest motors in its category so far. To lose so much weight while still producing the same amount of power — with the longevity we expect of Yamaha products intact — is quite an achievement.

It was interesting to say the least at the recent release of these new motors to hear Yamaha technicians talking about how they achieved such a dramatic weight loss. Obviously, the lighter weight of the new 225, 250 and 300hp motors has a lot to do with losing two cylinders and associated mechanical bibs and bobs. But it also has to do with exhaustively reviewing absolutely everything about the new motors and losing a few grams here and there wherever it could…that, and introducing new materials and some innovative new technologies.

A good example of the metal technology incorporated in this latest model line is the way Yamaha did away with steel cylinder liners in the engine block by introducing a new plasma fusion process to line the bores with material that’s 60% harder than steel — meanwhile saving more than a few grams, and making engine cooling more efficient.

Yamaha’s fly by wire electronic controls have also been reviewed in the new 225, 250 and 300hp V6s, along with the introduction of an upgraded integrated-engine-monitor system displaying on new 5-inch, high-contrast, high-definition LCD instrumentation.

Perhaps the most immediately noticeable improvement introduced with the new V6 series though is a new series of propellers designed to reduce the clunk so common with big-power outboards of all brands when they’re put into gear. Called SDS (Shift Dampener System), these new props creep up on you because you don’t really notice how smoothly and quietly they go into gear until you get out of a boat with an SDS prop into one without. Did gearboxes always clunk that much?

Like the F70, Yamaha’s new V6 225, 250 and 300hp 4-stroke outboards basically reset several standards. As the second of an entire new generation of motors, you have to wonder what comes next!

www.yamaha-motor.com.au

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