All powerful

Before deciding which mower will best fit your fleet, consider what's at the heart of the matter: the engine. Mower manufacturers frequently offer a selection of engines with their mowers that vary in horsepower and design. Here are some engines that are typical for commercial lawnmowers. If you need more information, use the circle numbers provided at the end of each product description.

Who: Briggs & Stratton

What: Vanguard 2/LC

Description: The Vanguard 2/LC is a new 2-cylinder, 27-hp engine designed especially for tough, commercial grade applications. The innovative design features liquid-cooled technology for longer life, the ability to accommodate more horsepower and cooler, cleaner and quieter operation. The engine has a 360-degree cooling water jacket to reduce engine and oil temperatures, increasing durability and extending engine life. An advanced air and oil filtration system further protects components and an industrial-grade centrifugal air cleaner ensures maximum engine protection even in dusty conditions.
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Who: Kawasaki Motor Corp.

What: FH721D

Description: Kawasaki has added the new FH721D — a 25-hp, horizontal-shaft engine — to its FH Series line of air-cooled V-twin powerplants. All FH-Series engines feature easy, reliable starting as well as low noise, vibration and emissions. Horsepower ratings of the FH Series engines now range from 13 to 25 hp. The engines also feature overhead valves, cast-iron cylinder liners and dual-element air cleaners, as well as full pressurized lubrication system for less internal heat buildup, top-access oil fill and dipstick, and spin-on oil filter for easy maintenance.
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Who: Kohler Co.

What: Aegis

Description: The horizontal-shaft Kohler Aegis combines an advanced liquid-cooling design, heavy-duty air filtration system and peak power and torque, fuel efficiency, long engine life and hassle-free maintenance. Three liquid-cooled models are offered, rated at 27, 25 and 22 hp. The engine's integrated, automotive-style radiator ensures that these engines run cool by keeping oil and cylinder head temperatures low and running temperatures consistent. The cylinder heads are cast from a lost foam process, resulting in improved cooling around the intake and exhaust valves and ports.
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Who: Kubota

What: E-Series

Description: Kubota's proprietary E-TVCS (three-vortex combustion system) technology seeks to minimize engine emissions while enhancing overall performance. By offsetting the direction of fuel injected into the swirl chamber, and designing the throat of the swirl chamber to match the concave recess on the piston head, the E-TVCS system activates diffusive combustion in the main combustion chamber. This reduces soot, unburned HC and CO emissions and produced less NOx than traditional direct injection systems. The Kubota E-Series is a sophisticated diesel engine with improved power output, fuel economy, engine start-up, reduced noise and cleaner emissions.
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Who: Yanmar Diesel

What: TNE

Description: With diesel engines lasting 5,000 hours or more, Yanmar offers its Clean & Silent liquid-cooled diesel engines in the popular 20- to 100-hp range with 12 direct and three indirect injected models. Semi-open deck construction with super-thin full metal head gasket and high top piston ring design reduce dead space and cool air pockets to run cleaner. The TNE series are fully emission compliant. Single side servicing and compact dimensions make space limited installations practical. Yanmar diesels run quieter by design with lower mechanical noise emissions.
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The term “horsepower” was coined by James Watt (1736-1819), an engineer who, the story goes, worked with mine ponies used for lifting coal out of mines. Watt defined 1 horsepower based on the amount of work a mine pony could perform in 1 minute (33,000 foot-pounds). This definition, as arbitrary as it is, remains today as the primary method of measuring power output of engines. 1 horsepower = 746 watts. (Yes, the electrical term “watt” come from the same James Watt.)

Horsepower, while important, is not the only factor that determines performance. Torque is also critical. Small, high-RPM engines can achieve the same peak horsepower of much larger engines, but don't have as much torque. By contrast, a larger engine that runs at a lower RPM may have much more torque, with similar horsepower. Higher torque can be created with the high-RPM engine through proper gearing, but the result would be an engine that constantly runs at high speed, and a short engine life. It makes more sense to use a larger, slower engine that can do the same work and enjoy a much longer lifespan.


The California Air Resources Board (CARB) has calculated that the cost to consumers of equipment that meets the Tier II (similar to EPA's Phase 2 standards) will range from zero to about $35 per unit over comparable equipment today.


According the U.S. Environmental Protection Agency (EPA), small spark-ignition (SI) engines of 25 hp or less contribute about 20 percent of hydrocarbon emissions and 23 percent of carbon monoxide emissions from mobile sources. These engines are used primarily in lawn and garden equipment, such as mowers, trimmers, leaf blowers, chain saws and commercial turf equipment.

Under the already-implemented Phase 1 emissions regulations, new small SI engines have had to meet emission standards for HC, CO, and NOx since 1997.

EPA recently adopted Phase 2 standards for small SI engines. For nonhandheld applications, these standards phase in between 2001 and 2007 and are predicted to result in an additional 60 percent reduction in HC and NOx emissions beyond Phase 1 levels. For handheld applications (such as leaf blowers and chainsaws), these standards phase in between 2002 and 2007 and will result in an additional 70 percent reduction in HC and NOx emissions beyond Phase 1 levels.

A key component of Phase 2 standards is the durability of equipment, such that engines will continue to meet emissions standards as they age, not merely when they roll off the assembly line.

One result of stricter emissions standards generally has been more widespread use of fuel injection, which helps engines burn fuel more efficiently. Fuel injectors also are necessary if an engine uses a catalytic converter. Are the days of the carburetor numbered? Perhaps. New automobiles no longer use them, and with the exception of the smallest equipment, they're becoming less common in grounds care as well.

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