Yamaha F300B Outboard Review

Originally published in TrailerBoat #300, October / November 2013.

As with most contemporary outboard motors, the four-stroke Yamaha F300B engine thoroughly illustrates the advances in marine engine automation. It instant power delivery and midrange fuel efficiency, combined with relatively light weight, make it unbeatable amongst four stroke outboard engines in this power range. It is simply the most technologically-advanced four stroke outboard to be sold in Australia, even though it is naturally aspirated and not supercharged like the Mercury Verado 300 competition.

YAMAHA F300B OUTBOARD

The OEDA three-star F300B is Yamaha’s top-of-the-line model and replaces the Yamaha V8 F300A — just as well, because it’s much lighter. Unlike four stroke motors produced by other manufacturers, the quad-cam 24 valve 4169cc V6 powerhead has no steel cylinder liners to add weight. Instead it has a 10 micron coating which was created by injecting powder into the path of a mix of argon, nitrogen, hydrogen and helium gas at mind-blowing temperatures. This creates a coating Yamaha claims is 60% stronger than steel. When combined with other weight savings, such as having the cylinder walls closer together than if steel liners had been inserted, the bare engine weight is just 126kg.

The Yamaha F300B outboard develops 299.9hp at 5500rpm with a Wide Open Throttle range of 5000 to 6000rpm. As it runs a 10.3:1 compression ratio, premium unleaded (95 octane) is needed, so don’t be tempted to try E10 to save a few dollars (and destroy your engine). The voltage-regulated alternator with dual battery charging capability produces up to 50 amps of dedicated charging current, while throttle and gearshift controls are “drive by wire”. Combined with the slipping prop hub, gear shifts are almost imperceptible.

Other features include some cooling water bleed from the impeller to cool the prop hub, plus cooling intakes at the forward end of the gearcase torpedo to supply water even when the leg is trimmed right out. The idle rpm can be adjusted in increments of 50rpm from 600 to 1000.

The gear ratio is 1.75:1 and dry extra-long shaft (25in) weight 253kg.

SERVICING AND MAINTENANCE

Servicing intervals are every 100 hours or annually after the first 20 and the serpentine camshaft belt has a designed lifespan of 1000 hours but should be checked annually for any fraying or damage, as the powerhead is an interference engine. Valve clearance adjustments are at 500 hours when the camshafts need removal but at least the powerhead doesn’t have to be separated from the pan as with chain driven camshaft engines. The oil sump is only 6lt so don’t extend the oil and filter change intervals. The recreational usage warranty for recreational anglers (and others as well) is four years.

ON THE WATER

Mounted on a Cruise Craft Explorer 685 and swinging a 19in pitch stainless steel prop, the review Yamaha F300B was the maximum power for this beautifully forgiving hull. The outboard started instantly, hot or cold, with no oil smoke appearing at any time or no “shift shock” when shifting from neutral to ahead or astern. While idling, the engine was very quiet with no vibration passing through the hull structure.

With the throttle “floored” from idling revs, the Cruise Craft hit planing speed — despite our 2400kg total displacement — in just over two seconds. At, or near WOT, there was a slight indication of all that mechanical complexity whirring away but less noisy than the Mercury Verado 300 and way quieter than the Evinrude E-TEC 300.

YAMAHA F300B PRICE

As of September 2013, the extra-long shaft Yamaha F300B outboard had a price of $32,000 RRP. A spare propeller had a price of  around $1000. Thanks to Yamaha Motor Australia, Murarrie, QLD (07) 3906 7000 for supplying such a well set-up demo engine. 

THE TRADE-A-BOAT VERDICT

It all comes together beautifully in the Yamaha F300B outboard motor, which frankly is a masterpiece of marine engineering. But make sure your local servicing dealer understands the engine or it may not continue to perform as well as Yamaha originally intended!

YAMAHA F300B PERFORMANCE

*Best planing fuel efficiency

COMPETING OUTBOARDS