REVIEW: 2017 Yamaha F25C Four-Stroke Outboard Engine

2017 Yamaha F25C

Priced from $4829

At the core of the new design was weight saving and at 57kg for a manual start tiller it is the class leader, even coming in under some two-stroke engines. Add the electric start (which you really don’t need – see side bar) and an L shaft, and weight creeps up to 67kg. Tilt is manual on the base model; with electric tilt and trim controlled though the tiller arm or by binnacle control at the helm available on higher-spec models. The alternator is a high 16amp unit, with an optional charging loom an easy dealer-fit option. The engine displaces 432cc and uses an overhead camshaft pushing two valves per cylinder.

Our test boats varied from a tiller steer 3.98m Creekmasta SeaJay to a Horizon 390 Stalker with remote steer and binnacle. Although fuel consumption is not the issue here that it can be with bigger engines, the numbers are impressive – the remote and tiller boats both managed 4.3km/L, according to Yamaha. What matters more to users are feel, sound, acceleration and smell.

You can forget bad smells – the F25C exhausts through the prop. Meanwhile, acceleration was impressive with both hulls lifting out of the water easily, right up to 40km/h. The F25C sounds as you’d expect – like a two cylinder – but it’s not loud or intrusive as many twins are. Where it matters, in mid rpm, it has a smoothness that’s easy on the ear. Feel, however, is not its strong suit – under 2000rpm it betrays the inherent balance issues of a parallel two-cylinder design. However, Yamaha has released a clever new mounting system that spreads the load wider on the transom, plus a new tiller-arm design that reduces vibration passed to the driver.

Most obvious at idle, the F25C has a decent shake to it, though it’s not too disruptive thanks to the new mount and tiller, and it disappears quickly as the revs rise. Running two up during testing, the F25C was a solid performer and was easy to use. The electric trim on the Horizon was smooth and fast enough while the tiller arm-equipped SeaJay was familiar and comfortable to use. There is no doubt the engine will be popular. The low weight finally makes a four-stroke a competitive option for a portable while the long warranty and Yamaha’s established reliability will soon make the F25C a regular sight around the estuaries and mangroves.\

F25C Key Technology

Battery-less fuel injection

Going against all I thought I knew about engines, Yamaha has created an electronic injection system that can prime and start an engine using only a pull-cord. Better idle, better power delivery with no heavy and costly battery; awesome.

Compact crank

Key to the weight and size reductions in the F25C is the new, single counter-balance crank. The previous F25 required a longer, heavier and more complicated crankshaft to reduce vibration.

Variable trolling

A great function that allows revs to be raised or lowered by 50rpm increments between 750-1050rpm.

Freshwater flushing

Built in from the factory, a handy port can be found under the cowl to quickly and easily flush your F25C with fresh water.

Easy-start decompression

The F25C can be had with battery start but the decompression system used for the manual set-up starts in one or two pulls. Cold or warm, on the hard or at sea, we had no problem starting.

Facts & figures

YAMAHA F25C

RRP FROM $4829 (plus rigging)

TYPE Inline two-cylinder fuel-injected four-stroke petrol outboard

RATED HP 25

DISPLACEMENT 432cc

WEIGHT 57kg (F25MHC)

LEG LENGTH 15 and 20-inch

GEAR RATIO 2.08:1

PROPELLER Alloy 11.25in three-blade F Series

ALTERNATOR OUTPUT 16A

EMMISSION RATING 3-star