Yamaha's new quarter horses

Yamaha has unveiled two new 25hp four-stroke outboards that it says will appeal to everyone from the RIB holiday-maker to the houseboat owner.

The engines, designated the F25D and the FT25F, share a common twin-cylinder 500cc engine but have different drivetrains.

The FT25F takes the lower unit, bracket and gearbox housing from Yamaha's F40 model. This gives the engine the deep gear ratio needed for turning a low pitch, dual thrust propeller -- just what is needed for heavy boat applications such as barges and houseboats.

The F25D is available in a multitude of configurations to suit everything from inflatables, RIBs, dinghies and barra boats. Buyers can choose from tiller or remote steering, manual or electric starting, manual or power trim and tilt and a transom height of 20 or 25 inches.

Weighing in at 78kg the standard F25D falls into the lightweight category.

Both engines come with Yamaha's four-year manufacturer's warranty.

While Yamaha uses EFI on most four stroke outboards from 30hp up, the two new 25s use the tried and tested single carburettor coupled with a prime start system and decompression device (for easier starting).

The prime start has a microcomputer that controls ignition timing and to tell the carburettor to deliver precisely the right amount of fuel on start up. The decompression device ensures that manual and recoil starts are light and easy.

While big twin-cylinder engines are prone to vibration, Yamaha engineers say they have beaten the problem by fitting a counterbalance to the crankshaft to smooth out operations. Yamaha claims the vibration and noise are among the lowest of outboards in this class.

Both engines exceed the 2006 USA EPA emission standard and meet the US CARB emission standards and the EU marine exhaust emission regulations.

Like all Yamaha outboards, the new engines incorporate leading edge anti-corrosion systems.

For full specifications and more details visit Yamaha's site here.