Mercury Diesel TDI gives Sunrunner 37 double the range and half the cost

David Chadwick’s got twice the range and half the fuel bills, after repowering his 3700 Sunrunner with Mercury Diesel’s world beating TDI technology. 

“It’s a fantastic outcome,” David said. “I don’t know why more people don’t do it. You can’t go wrong!”

A late-comer to boating, 51-year-old David only bought his first boat six years ago. That 2800 Mustang lasted just 12 months before he moved on to the Sunrunner. 

Based on the Gold Coast, David regularly took the family out for local cruises to nearby Morton Bay.

“But it wasn’t until 2010 when I went to Gladstone for work that I realised I couldn’t really go anywhere in the boat,” he said.

With a 600 litre fuel tank his twin 5-litre petrol engines only had a range of 150 nautical miles.

“I started carrying an extra 100 litres in jerry cans to get out to the reef and back but that’s just too dangerous,” he said.

That’s when he decided to upgrade to twin MerCruiser Diesel 225 TDI engines.

Mercury Diesel TDI engines, created with Volkswagen’s engineering excellence, deliver high performance from a compact and lightweight platform. Not only is there plenty of power and acceleration, they’re also quiet and frugal. 

“The new engines have easily halved my fuel costs,” David said. 

“The trip between the Gold Coast and Gladstone used to cost me $2,400 in fuel. But with the TDIs a good run only cost $900. Once I did it in terrible conditions in 4-5 metre swells and that only cost $1,200.

He used to have to stop three times to re-fuel, now it’s only once with his range extended from a mere 150 to 320 nautical miles.

And that’s not the only improvement. 

The new engines are slightly lighter so the Sunrunner sits higher in the water, and its overall performance has improved despite dropping 70 hp in total.

“It’s certainly a better boat,” David said. 

“It gets up onto the plane faster. With the old engines I had to stay at 16 or 18 knots or she’d drop off. Now I can sit on 14 knots, where these engines are really economical, and she stays up. The power doesn’t just die off like it did.”

David paired the engines with new Bravo 3 drives to maximise performance.

“To be honest I wasn’t sure about the need for the Bravo 3s, but the guys from Mercury persuaded me and now I’m glad they talked me into it,” he said. 

“The improvement and fuel efficiency are just fantastic.”