Mercury FourStrokes according to Anthony Brown

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Before you go any further, consider the following: this video was recorded while the engine was running in the background, that’s how quiet the new Mercury FourStroke outboard motors are.



Mercury has released five new engines in the Mercury FourStroke range: the 75hp, 80hp, 90hp, 100hp, and 115hp outboard engines. Mercury has also released the new Command Thrust gearcases for the 115hp and 90hp engines. Both are counter-rotating which means that for the first time in the Australian market, counter-rotating engines are available in this horsepower range. This makes them especially suitable for twin outboard engine fitups.



The new outboards use a 2.1lt engine, whereas previously Mercury used a 1.7lt engine. Obviously this means bigger engine displacement, but the engines have actually gone lighter.

The standard Mercury 115hp model weighs 163kg, 18kg lighter than the previous model. "They’re also 5 per cent lighter than our nearest FourStroke model and — get this — they’re four per cent lighter than our OptiMax direct-injection range," says Mercury Australia's Anthony Brown.



The weight reduction comes from the design of the new engines. The new Mercury FourStroke engines have less moving parts than a normal four-stroke outboard motor. However, this does not come at the expense of performance or the strength of the engine. Anthony Brown says more than 17,000 hours of testing went into the Mercury FourStroke engines, including no less than 5000 hours of endurance testing



You may not know this, but Mercury is also the largest propeller manufacturer in the world. The new Command Thrust gearcase accommodates a bigger propeller. The improved design has also been measured to provide 15 per cent less drag, which translates into greater efficiency. The shape drags less through the water, which means more thrust coming from behind, pushing harder, and steering better.



One of the more unusual features is the new SmartStart system. "You’re up fishing at the front and you don’t realise your motor is going because the four-stroke motor is so quiet. If you just restart it while the motor is going, the engine just stops," says Anthony Brown.

John "Bear" Willis agrees. "One big complaint a lot of people have had with all four-stroke motors previously is the fact that they are so quiet that you go to turn your key and you wreck your starter motor," he says. With the SmartStart system, the skipper simply restarts the engine and away you go.


Videos: Mercury FourStroke outboard motors

We spent a couple of days reviewing new engines in the new Mercury FourStroke outboard motor range. As you can see, our video crew was kept very busy, as was engine expert Andrew "Engine Man" Norton and senior boat tester, John "Bear" Willis. Here's what they had to say.

Mercury 80hp Four Stroke outboard motor

Mercury F80 FourStroke outboard

Don’t stress over this outboard wearing out. The Mercury F80 develops maximum power at just 5000rpm, way lower than competing engines.

Mercury Four Stroke 90hp

Mercury F90 FourStroke outboard

Loads of low-down grunt and efficient running made the F90 FourStroke Andrew "Engine Man" Norton’s pick of the lot.

Mercury 115hp Four Stroke engine

Mercury F115 FourStroke outboard

The F115 is quieter than its predecessors due to decreased load on the engine. It also planed faster when fitted with a new Command Thrust gearcase.

Mercury Command Thrust Gearcase

Mercury Command Thrust gearcases

The new FourStroke range isn’t just about engines. Mercury also redesigned its engine gearboxes to reduce drag and increase overall performance.


See the full version of this story in Trade-A-Boat #455, July / August 2014. Why not subscribe today?

Contact Mercury for a product brochure  |   Request a test drive

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