by Dom Wiseman

Yamaha has realigned its mid-range four-stroke outboard range with the introduction of the new F90 model, one of the most important engines in the Yamaha outboard line-up.

The introduction of the new generation Yamaha F90 will see the existing 80 and 100 horsepower plants discontinued, which means the the new range will now jump from the 90hp option straight up to the 115hp engine. While it seems a big step up between the two options after spending time on the water testing the Yamaha F90 we are convinced that those previously considering the bigger 100hp option will not be disappointed, such is the performance of the F90.

Some of the new technologies introduced with this engine will also filter through the entire four-stroke engine line-up.

It is going to be available in a tiller steer model and its release coincides with a range of new propellers, the K Series GP SDS.

WHAT YOU GET

The new Yamaha F90 is lighter than the previous model by approximately 10kgs. This is important from a power to weight ratio perspective. The weight reduction has been achieved by using the F115B’s four-cylinder power unit and adopting a single overhead camshaft design (SOHCs actuating four valves per cylinder. This design was first used on Yamaha’s F70A and allows the F90 to deliver weight savings while maintaining smooth and efficient performance.

Yamaha F90 2

Yamah F90 3They’ve also redesigned and change the power head design and configuration. Coupled that with a reshaped combustion chamber and used lean burn technology to deliver impressive fuel savings while also delivering more speed and acceleration.

For anyone using an array of electronics, which is most boaties these days, the new Yamaha F90 delivers 35 amps of charge at wide open throttle and still generates 28 amps at 1000rpm. This should keep the charge equal to or better than any drain from modern electronics.

Yamaha say that the SOHC 16 valve engine provides greater power and efficiency with optimum valve control and allows air to transfer quickly for excellent response and I can assure you that in the mid range the torque delivered is impressive. The ECU controls the multi-point electronic fuel injection system using optimum timing delivering increased performance. It also ensures a rapid start in all conditions.

The throttle is a 60mm size single bore throttle which minimizes intake resistance while the plastic manifold reduces noise and ensures smooth operation at low speeds. There is also an intake silencer to reduce intake noise.

The new power trim and tilt units have also been redesigned to be more compact and tilt angles can be adjusted with the tilt limiter. This will be particularly handy to avoid jamming your engine up against a bait board which can sometimes hang into the engine well.

Overall the cowling is more compact. The one thing they have not changed is the positioning or size of the engine mounts which means that for anyone looking to upgrade to the new generation model can do so easily.

ON THE WATER

We didn’t get to drive the tiller steer and while it may be suitable for some applications, I expect that most installations will be forward control. The engine is also compatible with Yamaha’s Variable Trolling unit which offers the ability to alter or fine tune trolling speeds in increments of 50rpm between 600 and 1000 rpm. This is a handy feature for lure presentations and is adjusted via a dash mounted unit.

Yamaha F90 4

As a forward steer unit, the F90 is impressively quiet at all speeds. We tried it in a variety of aluminium boats and found that you could hold a conversation at all speeds no matter the configuration. The idling noise is particularly quiet.

Release the shackles though and this engine is all performance. You can feel the power as you push down on the throttle and the engine springs to life. The improved acceleration and top end speed is evident. The only thing that is more impressive is the fuel economy. We saw some graphs that illustrated the F90 efficiency as better than that of the current 80 and 100 hp units.

It is perhaps in the mid range where the torque impressed most. At every throttle position on the way to wide open the engine had more to offer and noticeably so. I can see this engine becoming one of the most sought after behind the F70 purely due to its performance.

The acceleration is impressive. It’s quiet and powerful and rises onto the plane easily. The torque and overall speed is impressive and an improvement on the old engine. With the Yamaha F90 fitted to a 5.35m Bar Crusher we saw a top speed of 61km/h (33 knots) at 5700rpm with a fuel burn of 35.85 litres per hour while a more modest cruising speed of 33 km/h (18 knots) at 3500rpm delivered 10.85L/ hour offering a decent range from a 100-litre tank.

The Yamaha F90 is also fully compatible with NMEA 2000 which means it will share information with third party multi function displays. It is also a plug and play with the existing Yamaha command link displays available in back lit LCD or colour options.

OVERVIEW

The new Yamaha F90 is a well-engineered unit that I suspect will find its way onto many packages in that mid-sized boat category. The efficiency is impressive but the mid range torque is what really stood out for me. Many people say that the four strokes can’t match the two-strokes ¬†for torque but I’d challenge anyone to say the F90 is lacking in this department.

POSITIVES
Yamaha F90 1

  • Efficient
  • Torque

NEGATIVES

  • None that I could find

SPECIFICATIONS

Price: (from) $14,199
Type: 90hp Four-stroke SOHC 4 valves
Displacement: 1832 cubic cm
Bore and Stroke: 81.0mm x 88.9mm
Alternator: 35A
Weight: (from) 162kg
Fuel: Regular unleaded
Emission rating: 3 star

 

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  • Ryan Morris

    Yep… absolutely love mine. Running it on a 4.6m morningstar runabout. 38 knots on a good day… considerably more fuel efficient at top revs too. All in all… couldn’t be happier