For John D'Orlando, 3.5 horsepower just doesn't cut it anymore. When his customers pick their way along the line of walk-behind lawn mowers outside the TrueValue hardware in North Beverly, Mass., Mr. D'Orlando encourages them to think bigger - 5.5 horses, at least.
"People come in wondering about their blades," he says of those who report problems in cutting with their older machines. A quick sharpening helps. But as more local homeowners let grass grow higher, says D'Orlando - to keep it lush during dry spells or because they're too time-taxed to keep up - the job also calls for sending more torque to that whirring steel.
Big engines hold up best under heavy use, he says.
Enginemakers are happy to deliver. Where 3.5-h.p. push mowers represented the standard 10 years ago, today it's not uncommon to find slope-nosed 7.5-h.p. models looking poised for takeoff at stores.
"There's definitely a horsepower war going on," says Peter Sawchuk, lawn-and-garden expert at Consumer Reports magazine in Yonkers, N.Y. "More horsepower is considered better. [But] there are points in which more horsepower doesn't do much for you," he adds. "And we're probably well past that point."
Others say the boost simply affords buyers more choice. US consumers snap up some 6 million powered walk-behinds each year, according to the Outdoor Power Equipment Institute (OPEI). And they increasingly demand mowers that do more.
Some of today's models have a mulching function. Many use engine power to drive the rear wheels, a power assist that many baby boomers appreciate.
"If you just want to make tall grass short you can get a 3.5 or 4 [h.p.] and still get the job done," says George Thompson, vice president for communications at the Wauwatosa, Wis., firm Briggs & Stratton, a major US manufacturer of mower engines.
"A Kia will get you there, as will a Maserati," he says, comparing the cheap-to-exorbitant spectrum of cars to lawn mowers. "Obviously the Maserati has a lot more features on it. And a lot more horsepower."
Mr. Sawchuk can recall when basic, unmodified ride-on mowers - which sell at a rate of about 2 million a year, according the OPEI - came with 12-h.p.
engines. Now, he says, they run to 20 or 22.
Mr. Thompson could not say what horsepower rating currently sells best for Briggs & Stratton, but he says the average level has risen steadily through the years.
Sawchuk acknowledges the widening array of features that gulp more power. But he also suspects that a marketing mind-set lurks in the tall grass: If 5 h.p. is good, 7 is better.
"I used to work for Troy-Bilt and make rototillers," he recalls, "and we used to have this big argument." Technicians would tinker with 5- and 6 h.p. tillers, squeezing out performance.
"The sellers wanted 8. They were trying to sell horsepower," Sawchuk says, even though the pulley-and-belt drive system wouldn't really transfer more than 4 to the blades, and anything more was "for show only." (In most push mowers, he allows, the engine drives the blade directly, so there is no such power loss.)
With a 500-h.p. Dodge pickup truck now on the automotive market - it uses the V-10 power plant made for the Viper sports car - it's not hard to believe that "show appeal" continues to matter.
"Throughout human evolution there's always been a move toward more complexity in tools," says Meredith Small, a professor of anthropology at Cornell University.
She suggests that at some level men might think they can attract women with brawny lawn gear, laughing at the notion before recalling that she surrendered her own nonmotorized reel mower when a man entered her life.
"Now I own half of a lawn mower, and a snowblower, and a leafblower, and there must be more," she says. "And I keep thinking, 'What am I doing with all of these tools?' "
Much more sobering: the debate over mowers' environmental impact. Watch groups point to the significant amount of pollutants - from nitrous oxide to carbon monoxide to volatile organic compounds - still being unleashed by small engines, government-regulated only since about the mid-1990s.
The amount of pollutants from small engines continued to rise into the late 1990s, according to EPA statistics.
"As cars, trucks, and buses become cleaner, lawn mowers become a larger fraction of the pollution problem," says Frank O'Donnell, a spokesman for Clean Air Watch, a Washington, D.C., nonprofit.
Manufacturers say mowers shouldn't even be mentioned with cars, so low is their overall gasoline consumption.
"You use a lawn mower on average 25 hours in a cutting season," burning only a few gallons of gas, says Briggs & Stratton's Thompson.
Manufacturers also cite recent progress in engine design. The number of two-cycle engines, which have relatively high emissions, has fallen in relation to cleaner four-cycle engines, says Roger Gault, technical director of the Engine Manufacturers Association in Chicago.
And some mowermakers have made extraordinary leaps. Honda, a company known for wringing power and efficiency from engines of all sizes, is poised to introduce new low-emissions mower engines - primarily for ride-ons - with advanced electronic controls. Engine speed will vary automatically according to "load." Thick grass? The engine sends more power along to the blades.
Elsewhere on the environmental front, many mower companies have also made modifications that dampen engine noise, says Les Blomberg, director of the Noise Pollution Clearinghouse in Montpelier, Vt. They will probably soon turn their attention to what he calls deck noise, caused by the movement of the blades.
Mr. Blomberg tested some 30 lawn mowers this year as part of his organization's Quiet Lawns Project. "There are gas-powered mowers that are half as loud as others on the market," he says. (See his findings at www.nonoise.org.)
Firms including Briggs & Stratton also now produce highly rated no-spill filling containers that eliminate raw gas overflow during mower fill-ups. (Gas lost in this way can emit up to five times as much pollution as the same amount of gas burned.)
Pressure is also likely to build for so-called "after" treatments - such as the catalytic converters in cars - to handle whatever exhaust an improved engine still delivers.
In addition to advocating electric mowers, for example, California is reportedly pushing for new gas-mower emissions standards for 2007.
But by some accounts, manufacturers continue to push back - hard.
"Briggs & Stratton had a ferocious lobby campaign the year before last in Congress to try to prevent California from setting tougher air-pollution standards for lawn mowers, and they partly succeeded," says Mr. O'Donnell. "If you had believed them, lawn mowers that were cleaner would all have created fires and driven all the lawn mower [manufacturing] jobs to China."
In a compromise bill, Congress allowed California to proceed with its tougher standards, but other states were prevented from adopting the California standards, says O'Donnell. "Part of that compromise was that the EPA was supposed to set additional national standards for new lawn mowers."
In fact, proposed standards will emerge later this year for small "nonroad, spark-ignition engines," including those powering mowers, says Carl Simon, acting assistant office director for the EPA's Office of Transportation and Air Quality.
They will take into account new technology, says Mr. Simon, who points to his agency's success in regulating watercraft engines seven years ago.
"You look at some of these standards," says Simon, "[and] they not only have pretty good emissions benefits, but they also save the owner money because you end up with more fuel-efficient technology."
Fairly low list prices could help homeowners graduate to mowers with the power they might feel they need.
At TrueValue, where $200 buys a modern version of a retro-looking, person-powered reel push mower, $230 buys a PoulanPro walk-behind powered by a Honda engine to the tune of 5.5 h.p. - right in seller D'Orlando's favorite range.
The mower has a clean-air-index score that should please environmentalists, and it might answer a question that Cornell's Small asks - with a note of exasperation in her voice.
"Hasn't anybody," she says, "seen the price of gas lately?"