Features Technical John Deere’s new king of the hill
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John Deere’s new king of the hill

In September, John Deere expects to begin offering the company’s most powerful diesel

A 6-cylinder 13.5-liter electronically controlled, turbocharged PowerTech.

“Our customers have been asking for more powerful engines, and we’re pleased to offer them this new model with up to 750 hp,” says Dave Flaherty, marine marketing manager for John Deere Power Systems.

The engine, PowerTech model 6135SFM75, should be a good candidate for powering large trawlers and sportfishing boats, says Thomas C. Lekar, manager of John Deere marine engineering. “We typically design engines with lower-rated [rpm] speeds, and lower-rated [rpm] speeds mean better fuel economy,” says Lekar. “You have a slightly smaller bore and longer stroke, which is inherently good for fuel economy and for strong power curves and low-speed torque. That’s where John Deere is different.”

The new PowerTech model overtakes the 610-hp 12.5-liter John Deere as the company’s most powerful recreational marine diesel. The engine weighs about the same and shares the same footprint as its lower-horsepower sibling, but the 750-hp version’s increased displacement, along with some internal engine design modifications, have allowed John Deere engineers to pump up the power, says Lekar.

Two additional diesels are scheduled to hit the market next fall: a 6.8-liter 330-hp 6-cylinder (6068AFM75) and a 9-liter 500-hp 6-cylinder (6090SFM75). The engines, which are turbocharged and electronically controlled, should find homes in cruisers, trawlers and houseboats, says Flaherty. Expect to see them in trawlers from Kadey-Krogen, which offers John Deere power exclusively, according to Tom Button, Kadey-Krogen vice president of operations. John Deere’s current 6.8-liter engine powers four different trawlers, he said, the 44, 48, 55 and 58.

In addition to fuel efficiency, John Deere engines are noted for their low noise and vibration levels, says Lekar. The high torque at low speeds translates into quick and powerful helm response.

The new engines will likely be good choices for boaters who are repowering, says Lekar. “We’re still heavy into repowering,” he says. “One of the advantages is typically they’re quieter than the engine being replaced, and we commonly see fuel economy gains of up to 20 percent.”

 

See related articles: 

- In tune with your inboard

- Volvo brings joystick control to its sterndrives

 

This article originally appeared in the May 2009 issue.

 


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