Latest News

Going to the Extreme with Yanmar

A new 28-seater jet boat was recently added to the Jet Boat Extreme fleet in Queensland’s thrill capital, the Gold Coast. Twin Yanmar 6LY2A-STP inboard diesels are the engines of choice for this experienced operator, and it doesn’t take long onboard one of their boats to understand why!

Jetboat Yanmar

The Yanmar 6LY2A-STP continues to be one of the most popular marine diesel engines for the brand and is the jet boat-driving powerhouse of choice for Michael Gilmore.

Michael owns and operates Jet Boat Extreme on the Gold Coast with the help of his wife Christine and sons Kegan and Macauley. Jet Boat Extreme launched a new 28-seater jet boat into its fleet recently, powered by two of these 440mhp Yanmars.

It’s far from the first time they’ve relied on Yanmar however. “Power to weight is one of the biggest advantages of the 6LY,” says Michael.

He should certainly have a good handle on such technicalities too – having designed and built all the jet boats in his fleet with the help of a naval architect and professional marine fabricators. Yanmars have gone in to each one, (including a pair of 315hp Yanmars in the first 18-seater operated by the business).

With 20 years in the jet boat business behind him, (and a life-long passion for speed on the water), Michael knows a thing or two about these thrill machines and takes pride not only in the design and safety of the boats, but also a strict maintenance regime.

IMG 2221
Michael Gilmore from Jetboat Extreme

Open the engine hatches, (below very sporty targa bars that also cleverly provide good air intake), and the trained eye will notice large engine room spaces for vessels that are under 8metres in overall length.

Roomy engine spaces are invariably the mark of a designer that knows the importance of engine maintenance, and Michael makes no secret of his insistence on clean oil in his machines.

“These engines are running at least 6 hours per day and they are run hard,” Michael explains. “They are expected to go for an hour solid on each trip usually, and we change oil and filters every 150 hours,” he said. Whilst the factory advisory for oil change hours on a Yanmar are significantly more than 150 hours, Michael believes there is no substitute for regular oil changes.

Another single engine jet boat he is currently refurbishing will have its 3,000hour-plus Yanmar 6LY2A-STP put back in it without a worry according to Michael.

“There’s very little that can go wrong with them and I like the simplicity of the 6LY’s, they have really served us very well.”


The straight six-cylinder design of the 6LY2A has of course been a popular configuration of marine inboards for some time, given the ability to slot such a block lower into the “V” of a monohull. The Yanmar also has a nicely flatter engine top to complement its good power-to-weight, with easy to access maintenance and service points.

Diesel efficiency allows smaller fuel tanks, (the new 28-seater jet boat carries just 500 litres for its day’s work), and the engine’s endurance abilities are something that can only be achieved from a true commercially rated engine like the 6LY2A-STP.

On top of the form-fitting lifejackets and seatbelts for passengers, the benign nature of a diesel fuel source is also a nice safety advantage in these boats.

Coming in at just over 500kg, the 6LY2A-STP engine delivers all of its 324kW (440mhp) at 3,300rpm. Its 5.8L displacement does not create an overly noisy tone however, even within the almost military-grade build of a hard-working jet boat.

These are boats that are built to thrill and in the hands of Michael or his skilled team of experienced skippers the Yanmar power certainly delivers thrills by the bucket load!

Connected to Hamilton jets, Michael prefers to keep things simple and the right-handed helms of his machines sport a very simple workstation: Cable-controlled single pedal throttle at foot and lever bucket control on the right-hand bulkhead provide the go and slow, whilst hydraulic 1.5-turn lock-to-lock steering does the pointing of these nimble speed machines.

Whilst limited to 40 knots on their Gold Coast waterways, these machines can turn on a dime and (literally!) spin full-circle on the nose when skippers use their controls the right way. They’re impressive to watch and far more fun to be onboard.

Power Equipment was given the opportunity to see Jet Boat Extreme’s new 28-seater put through its paces on the Gold Coast waterways, and the twin-Yanmar powered rocket did not disappoint!

Michael’s skippers take pride in their work and the Yanmars too. In most cases, these guys have driven jet boats of various kinds and they love the predictable, reliable power that is the 6LY2A-STP standard.

Next time you visit the Gold Coast, be sure to experience this Yanmar-powered thrill ride. You won’t be disappointed – book at jetboatextreme.com.au