5 things we like about Yamaha’s new jet ski engine

The new four-stroke, four-cylinder 1898cc engine replaces Yamaha’s 1812cc high-output engine that we’ve previously seen used in personal watercraft in Australia. 

According to Yamaha, the new engine is more powerful – the one it replaces is believed to have produced around 180hp, with the new engine increasing performance to 200hp – which in turn provides quicker and smoother acceleration and a higher top speed.

In summary, this is achieved via a larger displacement that helps with low- and mid-rev torque, redesigned intake and exhaust routes, and a 10 per cent larger throttle body that increases responsiveness and power production.

The new engine will be fitted to Yamaha’s WaveRunner VX Cruiser HO, VX Limited HO,  GP HO, FX HO and FX Cruiser HO models.

What, then, are the five key features we like about this engine?

In the US, Yamaha produces a range of locally designed and built inboard-engined boats alongside its range of personal watercraft.

This new jet ski engine, then, is also built to power boats, giving the factory economies of scale compared with other impeller motor makers.

In the old 1.8-litre high-output engine, water to cool the regulator and rectifier was drawn from the exhaust manifold.

In the new 1.9-litre engine, the water is now drawn from the cylinder head, allowing the regulator/rectifier to operate at maximum efficiency and power an ever-changing suite of ever-more advanced onboard electronics.

Yamaha has worked on the taper on the new throttle body, removing it for a smoother, crisper throttle response.

According to Yamaha, this makes the new 1.9-litre HO engine “an honest competitor to other brands’ supercharged motors”, a claim we’re keen to verify. 

The new throttle body design also moves the engine’s electronics inboard for better protection during service procedures.

The 1.9-litre HO engine relocates the oil filler and the thermostat to make them easier to reach, has an easier-to-access crankcase anode, and has a new intake manifold design featuring long runners and a flatter outside shape for easier engine removal. 

Meanwhile, the 1.9 HO’s crankcase assembly has a new shape, while a shape change at the cam gear location allows easier access for maintenance and better oil flow throughout the engine for improved lubrication and cooling.

Owners lift the covers to look at their jet ski engines, so Yamaha has modernised the look of the 1.9-litre HO engine with an all-new black anodized engine cover and exhaust manifold for a sleek, powerful, high-performance look. 

The engine cover is also one of the first Yamaha-made parts to include plant-derived cellulose nanofibre-reinforced resin. 

This resin is around 25 per cent lighter than existing material, reduces the amount of plastics used and carbon dioxide generated in the manufacturing process, and is much easier to recycle.