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John Deere D140 Problems and Troubleshooting Guide

John Deere is a respectable lawnmower brand with many fantastic machines in its list of products. They offer a wide variety in their catalog, which means even if you want to go with a premium, high-end mower, there’s a good chance they have one that you will like.

But today, I’ll be talking about one of the entry-level options that many landscapers pick up as their first lawnmowers – the John Deere D140. It’s an affordable lawnmower with plenty of power in the tank to tackle small to medium-sized lawns with little effort.

However, with affordable lawnmowers, there’s always that nagging question – are there any issues that I need to worry about? What exactly am I sacrificing with this mower?

Frankly, yes – there are a couple of issues with this lawnmower, but most of it comes up because of poor maintenance. And the good news is that any issues that occur in the John Deere D140 can also be fixed pretty easily.

In this article, I will address some of the common problems that users can face with the John Deere D140 and help you figure out how to fix them. So without further delay, let’s dive in.

John Deere D140 Problems

5 Common John Deere D140 Problems and Their Fixes

As I said, there are a couple of issues that can occasionally come up with your John Deere D140 lawnmower. Issues like engine malfunctioning, transmission failing, or inefficiency in fuel usage can be pretty common.

The good news, though, is that almost all of these issues are fixable. So here is a quick look at some of the common issues in John Deere D140 and their solutions.

1. Engine Issues

Engine Issues

Now when I say engine issues, a lot of things can fall into this category. An engine is a pretty complicated component, and any problem in its mechanism can cause your mower to stop working.

One of the main reasons behind engine issues in a lawn mower is oxidation which is a result of outdated gas in the tank. If old gas in the tractor is left inside for a whole winter, for example, it will start affecting the engine progressively until it ultimately fails.

Other engine issues include overheating or sudden loss of power while you are operating the mower. These two symptoms come up when the ratio of fuel and air mixture inside the mower is disrupted, causing one element to become greater than the other element.

If the reason behind the engine issues is old gas, you should change it as soon as possible. I personally always recommend using high-quality gasoline with your mower as it does not oxidize easily and can also remain usable for a long while. Ethanol-free gases are also a great choice.

On the other hand, if the main culprit behind the engine issue is the fuel to air ratio, then you have to rinse out the tank completely and reapply a fresh, new premix.

2. Transmission Issues

Transmission Issues

Another component in the John Deere D140 that is prone to issues is the transmission system. If you suddenly notice the speed of your mower drop significantly, then chances are, the transmission system needs a checkup. This is a pretty common issue and nothing to worry about.

However, before you start checking the transmission system, inspect the body, fuel level, engine, and all the other components that you can check without opening up your vehicle. This will help eliminate any other issues that might be affecting the transmission system.

To check and repair the transmission, you need to disassemble it. If the transmission box looks damaged, then that is the reason why your mower can’t move as it used to before.

You will also notice that there is no fill cap or drain stop in the transmission. Don’t be alarmed – since John Deere mowers don’t require filling or draining, this is natural.

However, if the viscosity of the fluid is changed in any way, the transmission system will fail. If that happens, then you have only one option – go and get a new system to install in your vehicle. But since installing a new transmission is easy enough, this means you can repair your mower to live another day.

3. Issues Starting the Mower

Issues Starting the Mower

Sometimes, you might notice that your mower absolutely refuses to start up. This can be an annoying issue, sure, and if you have exhausted all your options, like restarting it, inspecting the battery, and the whole works, then let me try and help you find a solution.

There are a couple of different ways to handle this problem. The first, and perhaps the simplest, way to solve it is to use a voltmeter.

  • Set your voltmeter to DC and attach the wires to the negative tunnel of the battery. Then connect the positive side to the solenoid starter.
  • Once the wires are connected, turn the key to see if the mower fires up.
  • Also, keep your eyes on the voltmeter to see if it gets a reading.
  • If there are no readings, this would indicate a starter failure.

In the event of a starter failure, the battery needs to be checked. You can test it yourself, but I would recommend taking it to an auto repair shop. If the battery is the issue, replacing it usually fixes the problem.

4. Electrical Issues

Electrical Issues

Now, while the battery is usually the main component that causes starting malfunctions, sometimes electrical problems can also be the real reason behind it. If you see that the transmission is fine and the battery is also functional, it’s time to look at the overall electrical system.

The first thing you need to check here is the spark plug. To fix any issue with the spark plug, you need to take it out of the engine. You can use pliers and a wrench to make things easier for you.

Clean the spark plug thoroughly using sandpaper or an emery board. You can also use your hands. This is a pretty sensitive component, and any leftover dirt or debris can cause it to malfunction. Once cleaned, set the metal connector tightly back in place.

You also want to look for any signs of rust. If it is indeed corroded, then you need to replace the spark plug. Since these are pretty cheap, that shouldn’t be much of an issue.

5. Inefficient Fuel Usage

Inefficient Fuel Usage

If you find that the mower is consuming more fuel than normal, then there might be a couple of different things wrong with your vehicle. You need to check for cracks in the gas hose and the fuel pumps to figure out where the problem is coming from.

If the gas hose is fractured, you need to replace it. Just buy a new one, remove the fractured one from your vehicle and install the new hose and you are good to go. When installing the new hose, make sure you start at the bottom.

Then slowly make your way to the valve cover. Even if you are a complete beginner, this shouldn’t take too long. If the issue comes from dirt piling up at the bottom of the fuel pump, then you need to disconnect the hose.

This will allow the gas to flow freely. Wait a while so that the gas can escape, and then reconnect the hose to the filter. Then blast air into the gas line, and the pressure will help clean out the line.

With any luck, this should eliminate any fuel inefficiency in your John Deere D140 tractor.

Frequently Asked Questions

Here are a couple of questions that I have often seen people ask about the John Deere D140 lawnmower.

What type of engine does the John Deere D140 feature?

The John Deere D140 tractor comes with a 2-cylinder Briggs & Stratton engine. It has an automatic drive system and an electric power take-off (PTO) system.

Is the John Deere D140 expensive?

No, the John Deere D140 is an affordable lawn mower/tractor that is catered towards people on a tight budget. It is the perfect solution for landscapers who want to keep their front or backyard grass in good condition.

Final Thoughts

The John Deere D140 is a pretty amazing mower for the price. Sure, it holds no candle when you compare it to something like the John Deere Z525e lawnmower, but it’s no slouch either in its price range.

That being said, it is natural for the mower to struggle in some aspects as the manufacturer had to cut corners to make the machine affordable. But since most of the issues in the mower are fixable pretty easily, this mower is an excellent pickup if you are on a tight budget.

I hope my complete guideline on John Deere D140 problems could help you identify why your mower is acting up and what you can do to fix it. Good luck!

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