Cut It Down To Size: Kunz Mower Deck

Implements/Attachments — By ATV Mag on March 13, 2009 at 12:00 pm

It’s kind of fun when even the manufacturers of a product are amazed by their invention’s capabilities.

We saw it happen in northern Illinois last fall. Our mission: Visit Kunz Engineering at the company’s headquarters, learn as much as we could about their industrial-strength, pull-behind mower decks, then take them out in real world conditions and put them to the test.

Founder Gary Kunz and Vice President Matt Kunz, his son, are very proud of their AcrEase rough cut mowers’ capabilities. They’ve been manufacturing, testing and refining their products for 17 years and will confidently boast about the machines’ abilities to trim not just grass and ditchweed but small saplings with a single pass.

But when trimming in the back-country with us magazine guys watching, Gary pointed at a more sizable tree and suggested his deck could most likely knock that down. Matt gave a shrug and a nervous glance at us – obviously not wanting to get caught taking too big of a risk in front of prying eyes.

Gary proceeded, and the rest is history.

Meet The Inventor
Gary Kunz reminds me a lot of my late grandfather, Cleland Springer of Clayton, Wisconsin. When Cleland had a machine on the farm or in the shop that wouldn’t accomplish a needed task, he’d spark up the welder or torch and adapt it to make it work. His mechanical skills and creative mind earned him a local reputation as the guy to see if you had a mechanical problem that needed to be solved.

Not surprisingly, Gary Kunz has a similar mechanical background. He was working at an engineering shop in northern Illinois when an altruistic endeavor and some creative genius altered his future.

“I volunteered to mow a church yard back in the ’80s,” Gary recalls. “I started out with push mowers, and it was just taking too long.”
Soon he created ways to attach 20-inch wide push mowers to the back of his riding lawn tractor. He started with one, then two, and at one point had four different push mowers mounted at angles behind his riding tractor. The system worked, but it didn’t corner very well.

So, one winter he pieced together a 48-inch pull-behind mower. It worked so well that he built himself a 60-inch wide pull-behind mower deck the next winter. One design led to another, and when Kunz was laid off from his engineering job in 1992, he decided to turn building custom mowers into a profession. Kunz Engineering was born.

Meet The AcrEase
The Kunz family likes to say their mower decks are the strongest, most durable decks on the market. After spending some close-up time with their 44-inch wide machine, we have every belief in their claim.

The rectangular deck itself is all-steel, with a 10-gauge steel main deck and 7-gauge steel side plates. Kick it, slam it, give it overhead blow with a sledge hammer – you aren’t going to hurt it.

Beneath the deck, twin 23-inch, heavy-duty, Marbane-steel blades mount to bulky spindles. Kunz conservatively states that the blade will mulch up to 2-inch diameter saplings, but we saw it do much better. More on that later.

The blades’ height is easily adjustable between 2 and 8 inches above the surface, thanks to a single crank handle on top of the deck, near the motor. Eight turns of the crank equals roughly one inch of height.

Power for the residential unit comes from a 17.5 horsepower Briggs & Stratton Intek engine; those opting for the “professional grade” setup get an 18 horsepower Kohler engine. Both are low-maintenance, time-tested engines with electric start. The Kohler offers a bit more torque and is made for high-hour users like landscaping companies. The Briggs engine will work fine for the average consumer.

The deck mounts behind an ATV using an adjustable tongue that hooks onto the ATV via a farm clevis. The tongue allows for multiple options, making it possible to use the deck directly behind the ATV or offset to the right or left. A farm clevis is used to provide the maximum amount of pivot. Matt Kunz explained that a standard 2-inch ball hitch attachment provides just 12 degrees of motion before it binds up. A farm clevis allows 45 degrees of motion, and that’s important when mowing uneven turf or coming in and out of ditches.

A four-tire design further aides in ditch trimming, allowing the deck to go up and down embankments without bottoming out.

The 44-inch mower deck weighs about 520 pounds dry and retails for $3,095 with the Briggs engine, or $3,795 with the professional grade Kohler.

Putting It To The Test
Our test was conducted on the edge of lowland, where swamp grass had grown to over six feet tall and then laid down and worked its way into a thick, snarled, twisted mess by the time we visited in November. Your average lawn tractor wouldn’t make it 10 feet in this mess, but we weren’t testing a Lawn-Boy or Yardman.

With one 44-inch-wide mower deck offset behind an Arctic Cat and another 57-inch deck behind a Honda Foreman, we were ready for action. With a simple push on the start button, each Briggs & Stratton engine fired to life. A flip of a lever on each machine engaged the blades.

On each ATV we placed the transmission in low and attacked the swamp grass rather tentatively at first, slowly plodding along and watching the mower deck do its work. It effortlessly cut a clear path through the rat’s nest of grass, and the Kunz duo signaled to us to pick up our pace. We cut through the area faster the next pass, and still faster on lap three. On the fourth lap, when we were going about 15 mph, the engine died out – we had found the upper limit for these particular conditions.

With the super-strong spindles, blades and deck that Kunz Engineering uses, killing the engine is about the worst that can happen.

“In 17 years of doing this, I’ve never hit anything that prevented me from continuing to mow,” Matt Kunz said. “If you hit a big rock, it merely kills the engine. You just pull off of it, refire the engine and keep mowing.”

The Tree
Back and forth we went, making short work of the project, as the blades ate up the grass and left a wake of mulch. When one of us would get off a machine, Gary Kunz would climb aboard and further attack the area. And that’s when it happened:
After we mowed close to the edge of a grove of trees, Gary spotted the small tree. It was about 15-feet tall and had branched off in a couple of directions, as small, unkept trees are wont to do. This wasn’t a sapling, it was a tree – and Gary wanted to knock it down to size. Matt seemed unsure, but before he could talk his father out of it, Gary headed straight for it with the 57-inch mower, which features twin 30-inch blades and is powered by a 20 hp engine.

He slowly pulled up to and the over the tree – and the mower deck made a vicious, grinding sound as the blades attacked the wood. Gary kept slow momentum going forward, and when he passed, the tree had been eaten alive.

A tape measure showed the tree’s diameter, where it was cut, measured roughly 3.25 inches. “I think that is officially the largest standing tree that we have personally cut off,” Matt Kunz would later say. “I have had plenty of customers claim that they were cutting off 3-inch diameter saplings, but I thought that they didn’t really know for sure. I guess maybe they were right.”

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