Why Does John Deere Use Yanmar Engines? [What Is It & Is It Still Being Used?]

Since the early first half of the 19th century, John Deere has manufactured tractors and lawnmowers. For the most part, John Deere has always manufactured its own; however, in recent decades, some of the work has been outsourced, and there are a surprising number of manufacturers that produce engines for John Deere.

Yanmar is one of them, and while they don’t make all of John Deere’s engines, they do make a small fraction of John Deere’s engines, primarily when it comes to utility tractors. John Deere contracts Yanmar to build its utility tractor engines because they are the world’s best small diesel engine manufacturers.

Yanmar is a Japanese plant, and the company was responsible for the world’s smallest diesel engine at one time. Yanmar builds a pretty wide range of diesel engines for its own tractors, John Deere, and diesel engines that are used for marine applications. 

Yanmar’s History

Yanmar’s main plant is located in Tsukaguchi, Japan, and the company’s focus has always been on small and medium-sized diesel engines. Even though they have gone out of their way to produce a few gasoline engines that were excellent engines but nothing stands out in the history books. 

Yanmar’s history isn’t as extensive as John Deere’s, but they’ve still been around for over a century, getting their start in 1912 in Osaka, Japan. Initially, diesel wasn’t the company’s primary focus, which manufactured kerosene-powered engines at the time. 

Yanmar didn’t successfully manufacture and market a small diesel engine until 1933, and by 1992, it had surpassed 10 million diesel engines manufactured under its roof. Then, when the 70s rolled around, Yanmar and John Deere’s partnership began. 

John Deere (as a company) was looking for the best diesel engines for a new manufacturing design that required smaller engines. It was the compact utility tractor that John Deere had in mind, and at that time, Yanmar had made a name for itself when it came to small diesel engine production.

The partnership has lasted for over 50 years now and is still going strong. Currently, Yanmar develops and manufactures small diesel engines for a series of John Deere small utility tractors. 

  • Series 1 utility tractors with 24hp diesel engines
  • Series 2 utility tractors with 37hp diesel engines
  • Series 3 utility tractors with 35hp diesel engines
  • Series 4 utility tractors with 66hp diesel engines

That’s the extent of Yanmar’s partnership with John Deere, and it has been an ongoing partnership starting from 1977 through to the present day. 

John Deere Small Utility Tractor Engines and Drivetrain

If you pop the hood on one of John Deere’s range of small utility tractors, you will likely see the word “Yanmar” stamped on the engine block. While you may be initially irritated to know that John Deere outsources their small engine diesels to another manufacturer, there are plenty of reasons to be pleased with Yanmar.

Yanmar wouldn’t be where it is today, as one of the world’s best and most reliable small diesel engine manufacturers, if they didn’t produce quality work, even if that work ended up under the hood of a John Deere. 


Yanmar’s drivetrain components operate as effectively as expected from a John Deere tractor. It’s also reasonably easy to maintain. The transmission, axles, differential, and driveshaft are all part of what makes the utility tractor go and Yanmar keeps it all pretty economical, maintenance-friendly, and reliable. 

The drivetrain warranty is six years against all manufacturer defects. There is an additional 2-year warranty that covers other aspects of the engine as it is associated with the rest of the tractor. 

Engine Types

The Diesel engine that Yanmar produces for John Deere tractors is typically a four-stroke, liquid-cooled inline. It has a 1.6L displacement with a bore and stroke of 3.46″ x 3.54″. Now obviously, these numbers fluctuate based on the type of utility tractor in question, but the engine type remains essentially the same. 

The Yanmar small diesel engine has a 19.1:1 compression ratio, and the John Deere, 2032R compact utility tractor has a 32.5hp engine at 2,500rpms. It requires 3.4L for the oil capacity and another 4L in the coolant. 

Current Yanmar and John Deere Innovations

Yanmar and John Deere are looking at something that is a little larger than previous iterations in the small, compact utility tractors. In July 2020, John Deere announced that it was moving towards a new series of tractors in partnership with Yanmar, who would supply the engines. 

This new compact utility tractor would have what is called a Stage V compact tractor and, according to John Deere, would incorporate 13 different tractor models across 6 series. The new Stage V compact utility trailers will come with 1.6L, 3-cylinder engines that range from 19 o 48 kilowatts. 

The goal is to design a new, powerful engine for use in John Deere’s line of compact utility tractors that reduces emissions without sacrificing what made these engines great to begin with. 

Reducing emissions is achieved by lowering fuel consumption, expanding control and precision, and knocking down the operating costs associated with the Stage V innovations. Part of the manufacturing process will include:

  • A Diesel Particulate Filter
  • Improved oxidation catalyst
  • eHydro Transmission
  • eThrottle function
  • The improved common rail injection system
  • The improved electronic control unit

As of right now, it looks like Yanmar and John Deere will continue their decades-long partnership with a whole slew of new engine types that have already been introduced in the UK and are now stateside.

Is Yanmar John Deere’s Only Partnership?

When it comes to John Deere’s largest diesel engines, John Deere is the manufacturer from the beginning until the last nuts and bolts are tightened. We know that Yanmar supplies John Deere with small engines for Deere’s line of compact utility tractors; however, is Yanmar the only one?

They’re not. In fact, John Deere has several partnerships, most of which involve the development and manufacture of engines for various lines or series of John Deere tractors and lawnmowers. 

John Deere manufactures the vast majority of its engines; however, the above four have specific segments in which they manufacture engines for John Deere. The difference between John Deere and many other manufacturers is that John Deere modifies these engines after they are made. 

While John Deere is rated as one of the most reliable manufacturers globally, they modify their outsourced engines so that it is difficult to replace worn or defective parts in these engines with something outside of John Deere itself.

Some might find that practice a little irritating, but it’s understandable that John Deere wants to elevate its manufacturing over potential third-party establishments. 


For those who thought that John Deere was all in-house, there is liable to be some level of disappointment. However, John Deere doesn’t just outsource to anyone, and the engines that are outsourced are done so in a high-quality way that is thoroughly checked and modified at John Deere’s own facilities.

Related Articles