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Mercury 4 Stroke
2.5 HP - 25 HP
Mercury 4 Stroke 30 HP - 50 HP
Mercury 4 Stroke 60 HP - 115 HP
OptiMax

Though introduced only a few months ago, Verado already rules the world of
outboards. This revolutionary line of four-stroke engines is powerful and fast
enough to pull water-skiers with ease, yet quiet enough to let anglers sneak up
on fish. They don't guzzle gas, yet they get up and go with the flick of the
throttle. And EPA and CARB have awarded them three stars, which means they
already surpass emission standards for years into the future.
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The story of Mercury's four-stroke program reads like a cold war spy novel.
For what seemed an interminable period of time Project X was a shadow motor,
much whispered about, but never actually seen in the light of day. Then
after five years of anticipation and an investment of more than $100 million
the mystery motor came in out of the cold. Verado was born.
In the beginning Verado was available in 200-, 225- 250- and 275-hp, a 2.6
liter Inline-6. More recently 135 and 150 hp I-4s have become available
According to an inside source, eventually we might also see I-3s and I-5s.
And now after only a few months on the water the outboard is winning high
praise, including the coveted IBEX award for innovation. Here's a quick
overview of the technology.
Mercury engineers designed Verado from a blank sheet of paper. None of the
components are derived from automotive engines, unlike some competing
four-strokes. Also compelling, Verado is founded on an in-line cylinder
block where competing four-strokes are all V-4s and V-6s. Because they're
relatively skinny, multiple in-line Verados (twins and triples) can often
times be more easily rigged on a narrow transom.
Verados are intercooled and supercharged. The design includes
state-of-the-art cylinder heads, populated with four valves per cylinder,
actuated by double overhead camshafts (DOHC). These free-breathing
components, and especially the supercharger, lend Verado potent low rpm
torque. That's an important characteristic with a four-stroke, because
compared to two-strokes, they tend to be anemic at lower rpm. To compensate,
most outboard builders deepen the gear ratio to multiply torque. That means
the engine turns a higher rpm for a given speed. But the four-stroke Verado
gearset ratio remains a conservative 1.85 to 1 on the I-6s and 2.08 to 1 on
the I-4s., That's about what you'd expect to find on a two-stroke. Verado
maximum torque is generated at about 4500 rpm, with an operating range of
5800 to 6400 rpm. The bottom line:, a Verado outboard matches two-stroke
performance at any rpm. Fuel economy is also very good, with the 275 tuned
to burn premium, while the less powerful Verados burn the cheap stuff, 87
octane.
On any engine reliability is another characteristic worth looking at. Cast
pistons with individual oil galleries extract heat out of the skirt
extending life and maximizing horsepower. The block and cylinder head are
lost foam castings, albeit with a unique refinement. Aluminum shoots into
the mold under extreme pressure for greater density, yielding a particularly
strong and lightweight parts. Also, with its closed-deck cylinder block
there is no gap between cylinder walls and deck. That makes it stiffer.
Conventional cylinder head bolts have been replaced by special fasteners
that attach from below. Once again, that makes the assembly stiffer. Similar
to a Formula One race engine, a reinforcing plate girdles the crankshafts
main-bearing journals holding the crankshaft tightly in its grip. Built like
the Rock of Gibraltar Verado appears to be destined for a long life.
True to the state of the art Verado relies on an array of sensors to monitor
vital signs, and then adjusts performance, fuel economy and emissions to
compensate for fuel quality, ambient temperature, coolant flow and altitude.
Firmware pushes ignition advance and fuel/air mixtures right up to the
razor's edge, almost to the point of self destruction. It is the rock solid
block and crankshaft that allows the engine to hold itself together when
lesser creations would be pooling molten aluminum in the cylinder bores.
Beyond raw, a bloody horsepower, Verado's voiceprint is whisper quiet. At
idle the sound meter records a barely audible 52 decibels. At wide-open
throttle (WOT), it's still just 86 decibels. That WOT reading is so quiet
the wind and waves are sometimes louder than the engines.
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 4 Cylinder
135/150/175
6 Cylinder
200/225/250/275
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