John Deere Lawn Tractors: Should You Choose Gas or Diesel. Diesel lawn mower engine

John Deere Lawn Tractors: Should You Choose Gas or Diesel?

We hear questions like these often. My personal choice is almost always diesel.

1) John Deere diesel lawn tractors are robust, powerful machines.

If you have a larger area to mow, till, plow, etc., a diesel like the John Deere 430 can be a Smart choice. These tend to embody the “Nothing runs like a Deere” slogan, with the muscle you need to get the job done.

Powerful and efficient, diesel lawn tractors are well-suited in applications where you’re cutting through high grassy and/or wet areas. Most people find that they’re able to accomplish the job more quickly and effectively than a gas-powered counterpart.

When you’re talking diesel engines, a discussion of torque and horsepower almost always pops up. For instance, a 16HP diesel engine will have more torque than a gas-powered lawn tractor that has a higher horsepower rating.

2) A diesel lawn tractor is fuel efficient…

…especially if you’re using the tractor on a regular basis. While gas and diesel are both petroleum products, diesel has up to 12% more energy by volume versus gas.

What does this mean for you? You get up to 12% more output from the engine for each gallon of diesel burned as compared to consuming a gallon of gas. For those of you using your lawn tractor with regularity, this can result in an appreciable difference in fuel usage over a period of time.

Adapted from a post on Weekend Freedom Machines, here are some numbers for you that show how a John Deere diesel lawn tractor uses up to half the fuel when compared to a gas machine.

Just remember that actual fuel consumption will depend upon the conditions you’re using the tractor in, as well as the tractor itself (transmission type, hours, how well it’s maintained, etc.):

John Deere Tractor Model Consumption at Half Load Consumption at Full Load
316 (Serial #.285001) 0.9 GPH / 3.4 LPH 1.4 GPH / 5.3 LPH
318 0.9 GPH / 3.4 LPH 1.4 GPH / 5.3 LPH
322 0.9 GPH / 3.4 LPH 1.5 GPH / 5.7 LPH
325 0.75 GPH / 2.8 LPH 1.25 GPH / 4.5 LPH
330 0.4 GPH / 1.5 LPH 0.8 GPH / 3 LPH
332 0.4 GPH / 1.5 LPH 0.8 GPH / 3 LPH
345 0.8 GPH / 3 LPH 1.3 GPH / 4.9 LPH
420 1 GPH / 3.8 LPH 2 GPH / 7.6 LPH
430 0.4 GPH / 1.5 LPH 0.9 GPH / 3.4 LPH
425 0.94 GPH / 3.6 LPH 1.57 GPH / 5.9 LPH
445 0.98 GPH / 3.7 LPH 1.64 GPH / 6.2 LPH
455 0.79 GPH / 3 LPH 1.32 GPH / 5 LPH

3) Diesel garden tractors are built to last.

Will a diesel really last longer than a gas garden tractor? That’s the question everyone wants to know. The short answer is yes, provided you perform appropriate maintenance activities.

Consider that a typical John Deere gas-powered garden tractor has parts that can (and do) go bad. These include:

A lawn tractor with a diesel powered engine does not have these parts to break down or require replacement. In many cases, you can store a diesel garden tractor for extended periods of time and start it right up – try doing that with a gas mower.

Another advantage is that many diesel engines can run for thousands of hours before needing an overhaul. Liquid cooled diesel engines, such as the Yanmar 3TNA72UJ 3-cylinder found in John Deere 430 garden tractors, give the engine a more consistent operating temperature which can increase engine longevity.

Pros and Cons of Commercial Mower Fuel Choices

Running a professional landscaping business offers plenty of obstacles to overcome, from the right equipment to the right fuel. When the bottom line is at stake, every piece of information about efficiency of operation can make the difference between continued operations and an unsustainable business model. Just like with equipment, fuel choices can impact productivity, harmful emissions, and even noise pollution. At Scott’s Power Equipment, we know professional landscapers need to keep up to date on the best practices when it comes to creating better efficiency in their business operations. In that spirit, we’ve put together this short guide with some information about different types of fuel for commercial mowers. Read on for more about fuel and mowers, or head into one of our location in Missouri and Illinois. We serve Bridgeton, Arnold, and Wentzville, Missouri, as well as the entire Metro East area of Illinois.


The standard among commercial and personal mowers, gasoline is ever-present and easily acquired from local gas stations. Its convenient availability might be its best attribute, however. Gasoline engines are considered the low maintenance option when it comes to fuel, but this just isn’t true. The benefit here is mostly that gasoline engines are so common that most small engine repair shops only work on gasoline engines.

Gasoline-powered commercial mowers tend to have the lowest upfront cost, and because they’re so popular, there’s always some new technology that’s increasing their efficiency or reducing service intervals. If simplicity and convenience are your primary requirements for fuel, then gasoline is a great choice.


Diesel fuel offers a few benefits for commercial mowers. Diesel engines are more efficient than their gasoline counterparts. This means your overall running cost for a mower will be lower. Service intervals are longer as well, which means less time between tuneups. This goes for engine components as well, including less oil and filter replacement, as well as a reduction in the overall wear the engine experiences. That means diesel mowers can last significantly longer than gasoline mowers.

These benefits come with a price: diesel mowers cost more! Their engines are just more expensive to make, and diesel fuel is more expensive than gasoline or else more difficult to acquire without consideration. However, if you’re running a business and use your commercial mower every day, the longer life and more efficient running cost will give you a better deal in the long run.


Propane mowers become more popular as gas increase. Their biggest benefit is in the clean-burning fuel that has little environmental impact — a growing concern among landscapers. Propane engines don’t experience the same carbon build-up as in gasoline engines, making them last significantly longer (though not as long as a well maintained diesel engine). Many municipalities, government agencies, colleges, and homeowners associations require contractors to use propane-burning lawn mowers as part of sustainability efforts, so using a propane mower could turn out to be a competitive advantage for acquiring new clients!

Refueling propane mowers is a quick and easy process, usually as simple as disconnecting one tank and slipping another one in. That means more uptime for your mower and little worry of spillage. While propane isn’t as ubiquitous as gasoline, most gas stations have propane available, so it’s easy to stock up at the beginning or end of the day. However, this isn’t always the case, and some propane mowers only accept tanks designed specifically for the mower, making it much more difficult to keep a working supply of fuel on hand.

Each type of commercial mower fuel type has its advantages and drawbacks, but as long as you consider the needs of your operation, you’ll be able to find what’s right for you. For more fuel tips, or a look at a great stock of new and used commercial mowers, head into Scott’s Power Equipment. We have locations across Missouri and Illinois where we proudly serve Bridgeton, Arnold, and Wentzville, Missouri, as well as all of Metro East, Illinois. Stop by today and let our team of mower experts answer all your questions and help you find what you’re looking for.

Should You Get a Diesel Mower?

Just a few years ago, there was a massive gulf between gas and diesel-powered mowers. Diesel engines offered more power and better fuel efficiency but came with a hefty price tag. Today, that gap is closing as manufacturers have introduced fuel injected gasoline engines. Are diesels obsolete, or do they still offer superior performance?

Fuel Efficiency

The energy created by burning fuel comes from breaking molecular bonds, and diesel has bigger molecules than gasoline. As a result, a gallon of diesel has more potential energy than a gallon of gasoline. All things being equal, a diesel engine should use about 10% less fuel than a gas engine.

Diesels are even more fuel efficient due to their design. Diesels use compression ignition, squeezing the air/fuel mixture until it gets so hot it explodes. These engines use a high compression ratio to get compression ignition with each power stroke. Gasoline engines use spark ignition, lighting the fuel to create detonation. The compression ratio in these engines is low to avoid compression ignition. A higher compression ratio results in improvements to the air/fuel expansion ratio, intake velocity, and exhaust velocity. While you may need to be a professional engine builder to understand how these factors work together, they all come down to one result: compression ignition engines are a lot more efficient than spark ignition engines.

On average, a 25 HP diesel will burn around one gallon of fuel per hour, while an equivalent carburetor-fueled gasoline engine will use 1.5-1.6 GPM and a fuel injected engine uses around 1.2-1.3 GPM. That means a diesel will use ¾ of the fuel of the best gas mower.

How much can you save on fuel costs? That depends on the price of fuel where you live. Here in Pennsylvania, diesel is usually 0.50 per gallon more than gasoline, but it’s only about 0.30 more if you cross the border into Virginia. The savings can vary widely depending on this price difference and the total price of fuel, but even in the worst case scenario, you’ll spend less fueling a diesel mower.

Fuel Storage

Old gasoline will either cause corrosion from gasoline blended with ethanol or varnishing from ethanol-free blends in carburetor-equipped engines, while fuel-injected engines are usually fine as long as the fuel is stabilized.

Water contamination and algae growth can be a problem with diesel, but only if the fuel is improperly stored. Fuel can be left in a diesel engine for up to 6 months before any preventative maintenance needs to be taken, and that’s usually limited to running the engine long enough to flush old diesel out of the fuel lines.


This is easy to overlook, but it’s the biggest benefit when buying a diesel mower.

Horsepower is a measurement of work over time, and in this case, “time” is RPM. Gasoline engines make power at higher engine speeds than diesels, so they have higher horsepower ratings than an equivalent diesel mower. As with gas mowers, you can expect companies to match the output of a diesel engine to their equipment, even though on paper a diesel may seem less powerful than a gas engine.

With a wider torque Band and more low-end torque, a diesel-powered mower will be able to maintain blade speeds better than a gasoline engine. This is especially noticeable on mowers with 60 and 72-inch decks. Owners often report being able to climb slopes with the blades engaged where in the past their gas-powered mowers would only cut when driving downhill.

Reliability and Repair Costs

Fuel injection, better air filtration and improvements to lubrication and cooling systems have increased the life of commercial gas engines, but that also makes repairs more expensive. Diesels have always had higher repair costs, but they also have a reputation for long-term durability. It will be years before we understand how far new gas engines have come when it comes to reliability, but buying a diesel is a sure thing if you want to put as many hours on your mower as possible.


In the past, a diesel could easily cost a third more than an equivalent gas mower but again added complexity has closed the gap. Depending on current sales and financing options, the premium for a diesel may not be that much. Factor in fuel savings and the return on investment can be far shorter than the term of the loan.

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They’ve got the power: What you need to know about mower engines

Mower engines have come a long way since the first internal combustion engine (ICE) was put into a commercial lawn mower by Ransomes of Ipswich in England in 1902.

“Internal combustion engines are changing as government regulations and market competition increases,” says Ken Logan, product strategy manager at Kawasaki. “Of course, the physics hasn’t changed for ICEs — intake, compression, spark, exhaust — but the technology of how to do this has. power is coming out of engines while lowering fuel consumption, improving exhaust emissions and increasing engine life.”

Well over a century later, it is hard to even conceive of using a lawn mower that isn’t powered by an engine, especially if it is being used on a large commercial or residential property.

Recent developments and innovations in commercial mower engine technology can help landscape contractors save fuel and money. The power they afford can also help companies be more efficient, even if they have fewer employees, which is important in an industry experiencing a dwindling labor market.

Many of the latest innovations in engines have been introduced to enable mowers to cover more ground in less time, says Brett Wegner, product manager, Kohler Engines. “With tightened labor markets, productivity has become more critical because time is money,” he adds.

When it comes to a commercial mower engine, the fuel choice is perhaps one of the biggest deciding factors, and more efficient fuel consumption is one of the biggest recent advances in engine technology. Fuel and the rate at which it’s consumed can determine cost of ownership, environmental impact and engine performance.

“All different fuels have their place,” Wegner says. “The benefits depend on the type of equipment you’re using and the fuel source that’s most readily available and cost-effective for your specific use.”

No matter what type of fuel a landscape contractor chooses to use in his or her mowers, developments in engine technology ensure he or she will likely experience a cost savings, benefit from environmental friendliness and see an increase in power.

Saving green

“Certainly engine products today are far more efficient than they used to be,” says Kris Kiser, president and CEO of the Outdoor Power Equipment Institute. “One of the ways you get to emissions conformity is by reducing the amount of fuel you burn, so if you have an emissions requirement, you’ll burn less fuel. Engines have gotten far more efficient as of late.”

If an engine burns less fuel, it stands to reason that less money will be spent on fuel. Electronic fuel injection (EFI) is one innovation in engine technology that helps landscape contractors use fuel more efficiently, which in turn, saves them money.

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KEEP IT CLEAN Propane-powered mowers are cleaner burning than their gasoline or diesel counterparts. (Photo: Kohler)

EFI systems — which have been commonly used in automobiles for many years — work to precisely meter fuel in the engine to optimize performance and fuel efficiency. While some commercial mower engine manufacturers have been using EFI for several years, for many, it is still new technology.

According to John Deere’s engineering team, EFI reduces machine cost without sacrificing performance. EFI machines do not have carburetors, which often require routine maintenance or replacement — both of which can be costly and lead to downtime.

The sensor technology in an EFI engine optimizes performance by adapting to operating conditions.

“For example, in applications like an urban area where you’re doing a lot of transport time between parking lots and different areas where you’re not running the (power takeoff), it’s not consuming as much fuel because the engine doesn’t have to power all those areas,” explains Natalie Haller, product marketing manager for commercial mowing at John Deere.

The technology allows engines to continuously adjust engine performance in response to changes in operating conditions — such as external temperature and altitude.

Engines equipped with EFI technology are able to make adjustments as they run, so fuel is always being used in the most efficient manner, no matter the operating conditions and, most importantly, if the operating conditions change. Not only does this save companies money, but it also adds to the machine’s green factor.

IT’S ELECTRIC Electric or battery-powered mowers serve as options to completely eliminate emissions. (Photo: Mean Green Mowers)

The fuel system itself is constantly readjusting, measuring and tweaking its air-fuel ratio hundreds of thousands of times per minute and optimizes the performance of the engine to put out the least emissions and be as fuel-efficient as possible, says Jeremy Wishart, director of off-road business for the Propane Education Research Council (PERC).

EFI technology is now common on gasoline-powered engines, but there are only a few manufacturers that have adopted it for propane engines, according to Wishart. He says he expects several companies to announce EFI propane engines in the fourth quarter of this year or the first quarter of next.

Other efficiencies incorporated into today’s mowers that can save contractors money include: cast-iron cylinder liners; aluminum block; large capacity air, fuel and oil filters; high-performance spark plugs; and hydraulic valve lifters, Wegner says.

Fuel choice is another way contractors can save money on their mowers. Though gasoline is still the most common fuel of choice for mower engines, according to Briggs Stratton, switching to an alternative fuel like propane will cost more upfront but overall can help a company’s bottom line.

According to Wishart, unlike traditional fuels such as gasoline or diesel, propane is less susceptible to market volatility and less likely to see fluctuations in price due to weather, geopolitical conflict, a refinery going down or even regional price differences.

Because a landscape contractor can lock in fuel price with a propane retailer, he or she can more effectively budget for fuel, since generally, the price won’t change until the contract is renewed.

Going green

Environmental, or green, initiatives are top of mind for many engine manufacturers. As emissions regulations get ever stricter, companies must find ways to make their engines more environmentally friendly, which is another area where EFI comes in.

POWER UP Gasoline and propane-powered mowers offer the same amount of power to the engine. Diesel engines, however, provide more torque. (Photo: John Deere)

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“With older carbureted engines, you’re basically tuning it for one operating condition, and that’s usually max power. And max power equals max fuel consumption, unfortunately,” Wishart says.

Decreasing fuel consumption not only decreases the amount of money operators have to spend on fuel, but it also decreases the amount of engine emissions.

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Other companies have committed to developing engines that run on cleaner-burning alternative fuels. Propane engines have gained some traction in recent years due to their lower emissions and financial incentives from the government and PERC that can help make the purchase of new propane-powered equipment more affordable, Wegner says.

“Since propane is a cleaner-burning fuel, propane models are ideal for states that enforce Ozone Action Days, when mowing with carbureted gasoline engines is limited,” Wegner adds.

When EFI is added to an already clean-burning propane engine, the environmental impacts are lessened even further. And with more engine manufacturers jumping on board to develop propane EFI engines, they are becoming more readily available.

Other engine companies are embracing the green trend, not just by the type of fuel they use, but by what the engines themselves are made out of. Briggs Stratton’s commercial mower engines are comprised of 98 percent recycled aluminum.

“Not 100 percent of the materials can be recycled, but many of the materials can be,” says Michelle Gross, senior director of marketing for North America in Briggs Stratton’s global engines and power group.

Even diesel-powered engines, which have historically been some of the dirtier engines, are getting more environmentally friendly. “There have been significant strides in diesel, whether it’s injection or filtering because emissions requirements are tightening,” Kiser says. “Oftentimes the cost of fuel will dictate the product choice and selection. But certainly diesel manufacturers have made significant progress in making engines cleaner.”

According to Haller, the John Deere Z997R, which is a diesel engine, was in final Tier-4 compliance a full year ahead of the mandated regulation, just to support the cleaner emissions.

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Tier-4 emissions standards are the strictest Environmental Protection Agency (EPA) requirements for off-road diesel engines. According to the EPA, to meet Tier-4 emission standards, engine manufacturers must produce new engines with advanced emission control technologies, and in-use diesel fuel must decrease sulfur levels by more than 99 percent, since the emission control devices can be damaged by sulfur.

Kohler manufactures diesel engines from 9.1 to 134 HP for a wide variety of equipment. These engines are unique because they meet Tier-4 standards without the use of a diesel particulate filter, Wegner says. The diesel particulate filter removes soot from the exhaust of a diesel engine.

Not only is this part of the engine often bulky and inefficient, Wegner notes, but the filter can also be costly to replace. Being able to eliminate it altogether saves money and the downtime associated with engine repairs.

“We have a lot of faith in our manufacturers that they will be able to meet any emissions requirements,” Kiser says.

Mowing green

Josh Willis of Greenscapes Land Care, Worton, Md.(Photo: Tony Ventouris,

Ultimately, no matter what kind of engine a mower comes equipped with, it is important to find the one that is right for a company’s intended application, budget and fuel availability. Overall, gasoline-powered engines are still the most popular, according to Gross. One of the benefits of a gasoline engine is the prevalence of the fuel.

“For most commercial lawn mower applications, gasoline is preferred because it delivers proven performance and is relatively inexpensive, easy to use and readily available,” Wegner says.

Gasoline is everywhere at every fuel station in every town, Haller notes. It is not always easy to find diesel, and securing propane typically requires a contract with a local propane retailer.

It’s also likely that if a gasoline engine needs maintenance, a landscape contractor is going to be able to find someone who can fix it. “Gas engines are easier to service because most of the small engine repair shops FOCUS on gas engines,” Gross adds.

Performance-wise, propane and gasoline operate about the same, but there is a notable power difference when it comes to diesel engines, which do afford operators a bit more power under the hood, Haller says.

According to Haller, diesel provides more torque, so if an operator is mowing through thick or tall grass, diesel engines are going to give them more power and provide a better quality cut the first time around. Unfortunately, the power comes at a price. Diesel still has the stigma of being one of the dirtier fuels.

“Diesel has greater power density than gasoline, but it has a reputation to overcome … (Think of) that thick black billowing Cloud of smoke belching out of the exhaust you see from trucks on the highway,” Logan says.

Propane, while clean burning, especially when compared to diesel, has a stigma of its own to shake off. According to Wishart, landscape contractors often believe propane won’t afford them the same type of power they’re used to working with.

Wishart explains that all of the rumors landscape contractors have heard about propane-powered mowers are generally just that, rumors. “Give it a try on one mower,” he says. “You’ll experience that the power is going to be the same, the maneuverability is going to be the same.”

According to Kiser, as long as the correct engine is paired with the right mower, a user is going to experience the intended amount of power paired with the best fuel economy.

“There are a wide variety of engines. The key is finding what product works best (for your application),” he says. “Manufacturers are terrific at this. The key there is to identify what engine is best and then make them available in the marketplace.”


It stands to reason that the simplest way to save money on fuel and reduce emissions is to eliminate the internal combustion engine altogether, which some companies are doing by switching to electric or battery-powered equipment.

Electric and battery-powered mowers run on motors, rather than engines, and tend to cost a bit more upfront than their engine-powered counterparts, says Joe Conrad, president of Mean Green Mowers.

“Electric mowers are going to be a higher initial investment,” he says. “Most contractors find that it takes about one-third of the service life to obtain the return on investment. The last two-thirds of the service life savings is money in the of the contractor.”

Conrad says there are several reasons why landscape contractors may choose to switch to electric or battery-powered commercial mowers, including:

  • Customers requesting a green alternative that is nonpolluting;
  • Customers wanting quieter options; and
  • Contractors can more easily draw in new customers — or keep existing ones — by offering low noise and zero emissions.

According to Conrad, electric or battery-powered mowers also require less routine maintenance because they do not have belts, pulleys, hydraulics or oil that need changing.

“Electric mowers save money because of minimal maintenance and zero fuel to purchase,” he says. “They also save time since the mowers charge overnight and (operators) do not need to make trips to the gas stations during the day to fill up.”

Electric mowers’ lack of emissions is another upside for operators, according to Conrad. “Low noise, zero exhaust smells and very low vibrations mean less stress on the operator.”

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