Evolution of Homeowner Lawn Equipment and Engines
Kohler Courage Engines
I've found that earlier versions of the Kohler Courage engine, mostly made between 2003 and 2006, suffered from an array of teething problems including improperly torqued head bolts, air intake blockage problems, issues with the camshaft gears, head gasket failures, valve problems, and starter problems. The head bolt problem arose from a faulty impact gun at the factory. This caused cracked blocks and premature failure.
The air intake problem caused overheating and, if ignored, a cracked block. This problem is most prevalent on the larger, higher horsepower, 597cc versions of the Courage (models CV590, CV600, CV610, and CV620) and less often seen on the smaller, 535cc versions of this engine (models CV470, CV490, CV530, and CV540). In some cases, the problem is preventable with frequent changing of the air filter and pre-cleaner. This has not been a pervasive problem, but has arisen on a larger percentage of machines than acceptable and probably on many operated in very adverse, dusty conditions without adequate maintenance.
The plastic cam gears were improperly adjusted at the factory and subject to wear and chips on the teeth. This led to camshaft timing problems and running issues.
The head gasket failures were attributable to poorly designed and overly thin gaskets. Head gasket failure can cause oil leakage into the combustion chamber resulting in exhaust smoke and/or oil leaking from the engine. Insufficient oil frequently leads to engine failure. The head gasket has since been redesigned and is much thicker.
Valve timing and valve seating problems caused poor engine operation, severe roughness, loss of power, and exhaust smoke. In the most severe cases, the engine would not run.
Finally, there was a recess in the Bendix starter gear that allowed water to accumulate. This caused corrosion problems with the gear and in some cases, seizure of the starter shaft.
At this point, I have not seen evidence of these problems on later, upgraded versions after 2006, since Kohler apparently addressed and corrected these quality issues. There were no recalls on the earlier versions of the Courage engine, particularly those prone to cracked blocks. Kohler, however, provided free short block replacements to persistent customers. A short block is an engine block that requires reassembly with ancillaries (such as carburetor, air cleaner, etc.) and installation. Labor cost was at the customer’s expense.
Nevertheless, the Troy-Bilt Bronco generally employs the CV540, 535cc, Kohler Courage, which I prefer. Both Toro and Cub Cadet use the larger Kohler Courage and it is primarily these machines that have suffered from overheating and cracked blocks. As a result, both brands reputations were marred. Toro even switched to Briggs and Stratton engines for two model years and then returned to Kohler, apparently once they were convinced the problem was addressed. They still employ the 597cc version of this engine today.
I favor the predecessor to the Kohler Courage single, the Kohler Command single cylinder. This engine features hydraulic valve lifters and a forged crankshaft among other enhancements. During the late 1990s into the early 2000s, this engine was used on a host of upscale tractors including the Yard-Man DLX 600 series, selected Craftsman LT and YT models, selected John Deere L and LA series models, certain Scotts tractors, and others.
Recent Evolution of the Single Cylinder Engine
Let me add a little more history on the evolution of single cylinder lawn equipment engines. The larger version of the Kohler Courage was derived by boring out the smaller version (larger bore, same stroke) in order to compete as lawn equipment manufacturers continued to drive prices down while maintaining level marketing claims. Most brands, notably Craftsman, started claiming ever higher and higher horsepower ratings, particularly on their single cylinders, starting in the early 2000s. First, Craftsman labeled nearly identical Briggs and Stratton 501cc engines with anywhere from 17.5 to 19.5 HP, often during the same model year, to distinguish products (this drew attention from the FTC)! Then, Briggs and Stratton came out with a 540cc version of their tried and true 501cc INTEK single cylinder, again with no or few other changes to engine specs, with claims of up to 21 HP.
During the past 10-15 years, there have been no real advancements in tractor technology. Increasing competition led to rapid declines in price.
To achieve cost reductions, lawn tractor manufacturers resorted to de-contenting the structure and drivetrains of their machines with each new generation. In the engine department, they replaced V-twin engines with single cylinders displaying similar HP ratings on many machines, including premium models, in the race for market share. The drawbacks are that the larger single cylinders are somewhat less smooth, more noisy, and perhaps more prone to problems than their smaller single cylinder counterparts and certainly when compared to their higher torque V-twin predecessors. These characteristics are traceable to increased displacement and/or higher compression ratios (resulting in hotter operation) that are no longer ideal for single cylinders. At the same time, these changes frequently took place without the benefit of other enhancements to the motors (e.g., to oil capacity, intake, exhaust, cooling, etc.) to maintain reliability.
The Rush to Structurally De-Content Homeowner Lawn Equipment
In addition, manufacturers reduced content on other fronts. For instance, they replaced sturdier underpinnings and bodies with lighter, smaller chassis, fenders, hoods, and other components that are almost indistinguishable in appearance to most customers. This accounts for the predominant transition to MTD's entry-level chassis on most Troy-Bilt Bronco, Super Bronco, and Horse models and Yard-Man 600 Series tractors, all of which formerly used the premium chassis. Yet, just as Craftsman makes almost no two LT1000 models the same -- most have different real model numbers (found under the seat) -- not all Broncos, Super Broncos, Horse, or Yard-Man 600 Series machines are the same! Every once in a while, MTD apparently manufactures some of these machines using the premium chassis and components. This may happen because of demands from dealer networks who want the higher quality version of a particular machine in order to distinguish their product line from that of the big-box chains. It also happens when certain retailers, like Walmart, who have tremendous buying power, dictate how they want a particular model made. So, for instance, in 2005 and 2006, Walmart sold a terrific, superior Yard-Man DLX 600 series tractor built on the premium chassis with a Kohler Command Pro engine and all the premium features at a very reasonable price. Yet, the DLX looked just like another model sold elsewhere (same paint color scheme, hood, and general appearance), the latter of which received very poor reviews from customers and consumer magazines. Basically, the strategy backfired on Walmart resulting in poor sales of their superior and attractively-priced product. Sadly, they resorted to discontinuing the DLX and replacing it with other, cheaper MTD products.
The interesting conclusion from all this discussion is that very often, older is indeed better.
With each new generation, products become lighter and flimsier. This requires the consumer to be increasingly selective to ensure he is getting a decent platform. The marketplace is filled with an accelerating percentage of junk machines at very low prices. These tractors, although new, are unlikely to last more than a few years. The consumer has to find the exceptions, meaning the best quality platforms that are made. One can no longer assume that every Husqvarna brand machine has a high-quality platform. The other Husqvarna brands, including Poulan Pro, Johnsered, McCulloch, Weed Eater, Craftsman YT, and others you may not have heard of, are differentiated for various market segments. The same certainly goes for MTD's clones, which include Bolens, Yard Machines, Troy-Bilt, MTD, MTD Pro, Remington, White Outdoor, Craftsman LT, Toro LX, Cub Cadet 1000, and more.
Market Share and Who Makes What
By the way, Husqvarna was/is responsible for roughly 50%-60% of the market, mainly owing to Sears Craftsman, which were all made by Husqvarna until Sears changed their LT line only over to MTD in 2007. MTD is responsible for 30%-40% and growing thanks to Sears. John Deere and Simplicity account for the remaining 10%. Simplicity also makes all Snapper tractors and for two years a few select, very high-end Craftsman models, the CTX series. These are rough figures that are changing as we speak.
Consumerism and How I Contribute
Now, this must all sound very complicated, but this is how and why I got into refurbishing used equipment as a hobby after working on vintage machines. I like to help people and I get to do this by advising folks on used yard equipment purchases. At first, when I discovered sellers posting very misleading ads, I published articles and even put up posts on craigslist demystifying such things as model years and who made what. I even put up a post with 12 buying tips that included the following (with associated photos not shown herein):
When picking a tractor that's pretty, consider the following ditty.
...The first pic is an '04.
...The second a '98 to '02.
...Don't be misled
...Or this can happen to you.
...Make sure that you look.
...Compare before you get took.
...Don't buy the wrong year!
...Let the buyer beware.
Anyway, my "consumerism" (an example, entitled 'MTD Gold Comparison', appears below -- it will enlighten you on Troy-Bilt too) led to demand for me to do the 'ground work' and provide good used product. So, I embarked on refurbishing select machines. I deal only in high-quality platforms and avoid inferior chassis offered both by MTD and Husqvarna, the two main manufacturers of almost all homeowner tractors sold today. Ever since, I haven't been able to keep up with demand. Many customers refer their friends and acquaintances to me. Most machines are reserved when they are in their early stages of reconditioning. I deliver a finished product that is repaired, reconditioned, and serviced to factory spec. I'm passionate about and proud of what I do.
All article content and images copyright Jay's Power Equipment. All rights reserved.
Revised: May 08, 2014