SPOTLIGHT ON ENGINES: Engine-uity

Equipment in the lawn care industry has come a long way. “It used to be that a guy would buy mowers, and to an extent, that would be his lawn care business,” says Bruce Farrar, manager of off-highway communications at Cummins, Columbus, Indiana. “Now landscape contractors are buying skid-steer loaders and other equipment, so the field is getting more diverse.”

Even the mower industry is getting more diverse. And to fit the different types of mowers and the operators’ expectations of the equipment, engines are becoming more diverse and advanced.

MORE HORSEPOWER. Power in mower engines now reaches 33 to 36 horsepower, says Cam Litt, product manager of twin cylinder engines for Kohler, Kohler, Wis. When riding mowers became common among contractors about 20 years ago, the typical engine had 12 to 14 horsepower, Litt says, adding that the high end of horsepower has gradually increased since then. Engines are still made as low as 14 horsepower, adds Ron Weber, product manager of commercial engines at Briggs & Stratton, Milwaukee, Wis., but many of today’s mowers demand more power.

The increasing mower deck is one advancement driving the rise in horsepower, Litt says. “Cutters are running bigger decks, so they need more power to run them.” Higher horsepower also aids in the powering of mowers with attachments, he adds.

Power boosts productivity, which is important to landscape contractors and manufacturers alike, Weber adds. “Outdoor equipment manufacturers are telling us that with the cost of the machines, they need to cut as much grass as possible in the shortest amount of time to maximize the investment,” he says.

And horsepower should not be judged by the package in which it’s contained, Farrar says. Some engines have increased horsepower without increasing in size, giving the contractor a mower with more power that isn’t bigger or heavier. Because of the smaller engine the manufacturer may have room to include noise or vibration control in the mower, Farrar adds.

Other engines that up the power quotient include the twin-cylinder variety, which are common in mowers. Those who want more power generally opt for twin-cylinder engines because they have the capability for more horsepower than single-cylinder engines, Litt says.

FUEL UP. Engine companies may tout the newest technology on their products, but sometimes all that is lost on the end user. “From the operator’s point of view, with smaller equipment like mowers the concern is whether they’ll be able to get through the work day on a tank of fuel,” Farrar says. As a result, engine makers take that into account when they consider fuel-efficient engine designs.

Higher fuel efficiency is achieved by changing an engine’s configuration, Weber says. Internally, steps are taken to reduce friction. And, externally, letting the engine breathe as much as possible helps save fuel. “All outdoor equipment manufacturers expect us to have a smoother running engine,” he says. “It allows them to run more efficiently.”

Another potential fuel saver is electronic fuel injection (EFI), Litt says. The feature eliminates the engine’s carburetor because fuel is injected right into the cylinder. Engines with EFI cost about $1,000 more than engines without the feature, but this can save the contractor $400 to $500 in fuel per engine in one season over a carbureted engine, Litt says.

“Contractors who have a fleet of equipment with EFI see the biggest benefit at the gas station,” Litt says. “If a small operator has only one unit, there will still be a gas savings but he’s not going to notice it as much.”

Another advantage of EFI is that the engine is easier to start in all weather conditions and offers more powerful acceleration, Litt says. “Once you step on the throttle, you get a faster response,” he says, adding that starting an EFI engine is similar to starting a car in the sense that there is no learning curve. “With a non-EFI engine, you have to choke the engine and move the throttle a certain way,” he says. “Here you can get on, start it up and drive away like a car.”

The type of fuel an engine uses can also save contractors money. Gasoline and diesel engines burn fuel in different ways – the main difference being the fuel, Litt says. Gas engines are convenient to some contractors because the fuel is readily available. But some operators like diesel engines because they have several in their fleets, making it convenient to fill them all at once, Litt points out. Diesel engines can be more efficient, but the fuel is more expensive, he adds.

LIQUID/AIR DEBATE. Most engines used in the landscape industry are air-cooled, Weber says. But these aren’t the only option. Liquid-cooled engines, which are more common in large construction equipment, are sometimes found in smaller machines, such as mowers.
   
Liquid-cooled engines are perceived to be quieter and have a longer life, Litt says, adding they can retail at $300 to $500 more than air-cooled engines. Another benefit of liquid-cooled engines is that the technology can allow a quieter engine than some air-cooled models.

There are tradeoffs, though, Litt says. Liquid-cooled engines have more parts than their air-cooled counterparts, including a radiator, fans and belts, which means they require more maintenance.

The most ideal engine for a mower is determined by the application, Weber says, adding that liquid-cooled engines are often preferred by contractors in warm, southern states because they are thought to cool better and last longer than air-cooled motors.

But the life of the engine depends on the operator, Litt says. “If you take care of any engine, you will get a decent life out of it – no matter which one you use.”

Ultimately, the operator only thinks about whether the engine is going to be reliable and up to the task, Farrar adds.
“They need the product to run when they need it to run,” he says, adding that the operator wants a low total cost of ownership. “At the end of the day, what people really look for is low initial cost, low maintenance cost and high reliability.”