Yamaha outboard engines take technology to new heights

by Bob Wonders on 10 Dec 2009
The Yamaha Marine Group’s latest release, its all-new four-stroke offshore outboard engines, has been hailed as a ‘new generation’, with improved performance, 21st century innovation and technology and lighter weight.

According to Yamaha engineers, the new F300, F250 and F225 engines offer improvements at every turn when compared to earlier models.

For example, the new F300 V6 engine tips the scales at a massive 111kg (245lbs) lighter than the F300 V8 it replaces.

Described by Yamaha as ‘a big bore, 4.2-litre engine’, the F300 V6 offers enhanced performance and superior fuel economy.

The new V6, 4.2 litre powerhead is considerably larger in displacement than the company’s previous generation V6, 3.3-litre four-stroke. It also employs new materials and processes ensuring its status as a light, efficient and powerful engine.

The new technology sees the company using plasma-fused, sleeveless cylinders instead of steel sleeves, which provides a durable surface for the piston rings. Not only does this process reduce the weight of the powerhead, the material is only 0.1mm thick, taking up less space within the engine block than the conventional steel sleeve meaning more available room for the pistons.

This has allowed Yamaha engineers to optimise the displacement with the least amount of engine block mass and a consequent substantial weight reduction. Additionally, the process yields a surface that is 60 percent harder than a steel liner, the end result being greater durability, improved heat transfer between the cylinder walls and the cooling system leading to more efficient cooling all round.

Other weight saving measures include a composite engine pan produced from sheet moulded compound (SMC) which is more than 60 percent lighter than an aluminium version.

The SMC also offers superior corrosion protection.

Each of the new engines employs a new alternator that is nearly 3kg (6lbs) lighter than those used on earlier V6 engines, yet despite this it offers increased output.

Larger intake valves, larger exhaust valves and variable camshaft timing, allied with Yamaha’s Bank Exhaust System, which reduces back pressure and improves performance ensures these new engines boast outstanding acceleration.

Comparative fuel efficiency tests have revealed the Yamaha F300 V6 has shown fuel usage at 17 percent better than competitive 300hp engines.

Alternator output is now at 70smps as against the 45amps of the earlier models, meaning batteries charging faster and enhanced efficiency aboard vessels with a heavy load of electrical equipment.

An added ‘plus’ the new engines enjoy is a patented shift dampener propeller hub system that almost eliminates the loud ‘clunk’ that sometimes occurs on big horsepower outboards when shifting into gear.

Each of these new models is compatible with the Yamaha Command Link Plus system, which uses a single 5' high contrast colour LCD screen to display on-board functions.

Improved instrumentation adds to the appeal of the new engines; there’s even an ‘All Engine start-stop’ button which allows multiple engine installations to be started successively, preventing high amperage draw on the starting battery, and shut down simultaneously, all with the touch of a single button.


The new engines have already earned a three-start rating for ultra low emissions from CARB (California Air Resources Board) and already meet or exceed all Federal emission requirements.

Each of the new models will be available in 25' and 30' shaft lengths and in left and right-hand configurations.

For further information visit your local Yamaha dealer or check with Yamaha Motor Australia, Sydney, telephone (02) 9757-0011