Review: Yamaha F40F outboard motor

By: Andrew Norton

Presented by
  • Trade-A-Boat

What better outboard motor than the three-cylinder Yamaha F40F on your top ender tinnie?

Review: Yamaha F40F outboard motor
The Yamaha F40F is a well-engineered, reliable and precise outboard motor. Being a Yamaha engine, the resale value will also be good.

Yeah, I know four cylinders are better than three when it comes to outboard motor. But on a tiller-steer top ender around 4.5m you just don’t want the weight of a four-cylinder outboard or the lack of flab reduction when you’re a porker like me. Three cylinders still have some fat stimulation when trolling but won’t make your tiller hand numb as would a big twin.

The Yamaha F40F outboard motor was introduced in 2008 and replaced the three-carbie Yamaha 40 that had been around for about a decade. The finicky (a pain to tune) carbies were swapped for multipoint EFI yet overall weight increased by only 2.1kg. The result was an easy starting yet still straightforward to service 40 that returned excellent trolling and midrange fuel efficiency. And with Yamaha’s multifunction tiller arm, a masterpiece of design, driving a top ender became an absolute pleasure.

 

Yamaha F40F outboard motor

The Yamaha F40F outboard has a six-valve non-interference crossflow engine with belt-driven single overhead camshaft and the same pistons and conrods as the twin-cylinder Yamaha F25D and four-cylinder F60C, another incredibly popular outboard for larger top enders. As with these models Yamaha doesn’t fit an overhead manual recoil starter so bodybuilders won’t be able to show off, or weaklings like me pull their backs out!

At 15amp max output the voltage regulated alternator provides plenty of juice for onboard electronic toys. Powerhead access for the Yamaha F40F outboard motor is very good, with the engine oil dipstick and canister oil filter easily reached. At 2lt the sump capacity is large for a 40 and easily absorbs oil dilution that occurs during extended trolling periods.

The multifunction tiller arm includes an ignition key switch, attachment for an ignition cut-off lanyard, an upfront gearshift lever, variable trolling rpm switch, adjustable throttle friction and a trim/tilt button that remains in the same plane regardless of twist-grip throttle angle. This last design point is very important as the trim/tilt button changes position with one of the competition. As the throttle was opened the button position changed so that to trim out the leg the trim button had to be pushed down. Very confusing and an example of lack of forethought. Not so with the F40F which has typical Japanese design logic.

All that’s needed is a tacho mounted on a bracket attached to a sidedeck and who’d ever go back to a forward-control runabout?

 

Servicing and maintenance

Servicing intervals on the Yamaha F40F outboard motor are every 100 hours or annually after the first 20 hours. Valve clearance adjustment is done using a spanner and feeler gauge and the camshaft timing belt needs replacing every 1000 hours, though I’d check it annually for any fraying or damage. The warranty is four years.

 

Yamaha F40F on the water

Yamaha dealer Coast to Coast Boating supplied a review Yamaha F40F mounted on a Blue Fin Viking 4.5, a hefty basic top ender perfectly suited to this marine engine. The standard 12in pitch alloy prop matched the 2:1 gear ratio and the total displacement of 600kg, including two adults and test equipment. And no hydrofoil fitted to the antiventilation plate to rob the F40F of top-end speeds or create hull trim problems. God how I hate these abominations! If you’re driving one-up just carry three or four 20lt plastic jerry cans of water forward to trim the hull. Problem solved.

The Yamaha F40F engine started instantly hot or cold with not a whiff of oil smoke (manufacturers of DFI two-stroke 40s take note) and warmed quickly from cold. Providing the antiventilation plate was kept at least three-quarters immersed power astern was good and no cooling water starvation occurred, great for fishing skinny water. There was slight vibration when trolling, enough to gently massage my tiller arm but my tinnitus sure got a break that day.

Just a shame I reviewed this engine before acquiring my decibel meter but I estimate noise levels ranged from around 60dB when trolling to under 90dB at WOT, based on my testing of other engines using the dB meter which airport security staff keep mistaking for some kind of strange weapon!

Holeshot acceleration for the Yamaha F40F outboard engine wasn’t brilliant but once planing the engine was throttle responsive and oh so quiet out to WOT. The power trim worked quickly to trim the hull up or downwind and through tight turns at 4000rpm there was little prop ventilation with the leg trimmed in, amazing considering the Viking’s long keel. Even more surprising was how far the leg could be trimmed out at WOT before the prop blew out. Frankly the Viking/F40F was a helluva good combination and one I’d love to see behind my Triton cab chassis!

 

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The Trade-a-Boat verdict

Fitting multipoint EFI transformed this engine from its carbie predecessor, providing step-less power (no separate idle and main jet carbie settings) out to WOT and the 90-degree-turn twist-grip throttle gave precise control. The F40F is well-engineered and has proven reliability. And being a Yamaha outboard, it has great resale value too.

The review Yamaha F40F engine was supplied by Coast to Coast Boating, Morisset-NSW, phone (02) 4970 5541 or visit yamaha-motor.com.au.

 

Yamaha F40F sea trials

Single Yamaha F40F outboard motor on Blue Fin Viking 4.5. Average of two-way runs on Lake Macquarie-NSW over a chop to 30cm.

RPM

SPEED (KTS)

FUEL BURN (LT/H) NM/LT

 

750 (trolling)

2.6

0.6

4.3

3500 (planing)

11.1

4.6

2.4*

4000 (cruise)

14.6

5.5

2.7

5000 (max. cruise)

21.7

8.8

2.5

5800 (WOT)

26

12.6

2.1

* Worse fuel efficiency than when cruising due to higher engine loading. Sea-trial data supplied by the author.

 

Yamaha F40F specs

Yamaha F40F price: $8197 RRP

TYPE Three-cylinder EFI petrol four-stroke outboard

RATED HP 39.4 / 40 at 5500rpm

REC. RPM RANGE 5000 to 6000

DISPLACEMENT 747cc

BORE X STROKE 65 x 75mm

WEIGHT 99kg (dry, long shaft)

OEDA STARS 3

 

See the full version of this review in Trade-A-Boat #470, on sale October 1, 2015. Why not subscribe today?

 


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