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Suzuki’s innovative 25hp V-twin
  |  First Published: December 2005



The surprise-package Suzuki DF25 V-twin represents an all-new approach to lightweight four-stroke motors.

The DF25 is Suzuki’s first venture into V-twin four-strokes and the manufacturers say the 70° V-bank angle is wide enough to minimise vibration without heavy counterbalances yet narrow enough to provide a compact transom footprint.

The V-twin layout also moves the centre of gravity closer to the transom, enabling better balance and easier tilting. Although available in long and short shafts for tiller or remote control, only manual trim and tilt is available in all models at this stage.

The 538cc single-carburettor engine features two overhead valves per cylinder, housed within gleaming rocker covers, and the new CDI ignition is half the weight and size of previous systems. The central processor sets ignition timing while sensors monitor engine temperature and revs.

The dipstick and oil filter are easily accessible simply by removing the cowl and there’s a built-in water-separating fuel filter. With an all-up weight of 76kg for the electric long-shaft, this all speaks volumes for the motor’s potential as an economical workhorse on tinnies to four metres.

Horizon marketing manager Scott James set up a DF25 electric on the transom of a Horizon 415 Angler for a demo. With a length of 4.15m, beam of 1.95m, 2mm bottom, 1.6mm topsides, wide gunwales, short side pockets, battery and a low carpeted floor, this model would weigh over 180kg and recommended power is normally 30hp and up.

Idle speed on the test rig seemed a fraction high for dead-slow trolling but I’m certain you could tinker with this. With a twist of the throttle we were up on the plane in seconds and at 5300rpm we were around 20 knots once I moved back to the aft thwart to trim the hull to a fast plane. The 2.09:1 gear ratio certainly helps transfer torque to the prop.

There’s steering friction adjustment for longer trips but for someone who steers from the starboard side, the shift lever on the starboard front of the engine takes a little getting used to. I’d love to see this donk with power trim but I guess weight is an issue and there aren’t too many engines in this power range that come with it.

There’s torque aplenty, thanks to the V-twin design. Vibration and noise weren’t really an issue anywhere in the rev range and anyone who might have mentioned the word ‘Harley’ before they had a ride in this rig would probably come back with the word ‘Ducati’ on their lips.

If you’re contemplating 25hp power for the tinny you’d do well to take a look at this innovative engine.

– Tony Zann

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