John Deere D140 problems: Possible Reasons And Troubleshooting Tips

Yes, there are some issues but D140 is still a beast!

And worry; rather than spending an arm and a leg on mechanics, you can try our at-home solutions for traditional John Deere D140 problems and save a couple of bucks!

So, without any further delay, let’s get to fixing it.

Common Problems With John Deere D140

John Deere D140 problems

Let’s have a look at these problems first:

  • Engine Problems
  • Transmission Problems
  • Starter Problems
  • Electrical Problems
  • Fuel Problems

Let’s find out the reasons and solutions to these above-mentioned issues.

John Deere D140 Engine Problems

Among a whirlwind of reasons for your John Deere mower not complying with your commands, one of the usual prevalent troubleshoot has to because of the engine.

Let’s take a gander at some of the causes of engine problems in your lawnmower and plausible remedies to them.

Few Causes –

  • To put it simply, oxidized, old and obsolete gas in your tractor will eventually result in power loss. When this issue persists for too long, it gradually disrupts the engine’s mechanism causing it to fail untimely.
  • Another issue with the engine is overheating or losing power every now and then during a course of mowing. Similar to the first scenario, this could also happen when the premix in the engine gets corrupted, which prohibits the engine from starting or operating the mower accurately.

The Solutions –

  • If you boil down the reasons for being an old gas mix, you need to replace it soon. Often when gasoline gets combined with water, it can oxidize, causing such demise. Utilizing gas with a ten percent or lower amount of ethanol is recommended. Ethanol-free gases work wonders too.
  • On the other hand, if your premix has gone faulty, you’re left with no other option but to drain the gas tank and fuel line and flush out the contents thoroughly. Try implementing a new blend of premix.

John Deere D140 Transmission Problems

John Deere D140 transmission problems

A broken and interrupted transmission will pose the most typical concerns if you notice a slower or hesitant pace in the tractor. Some lawn owners faced the same issue with the John Deere LT155 mower too!

Just like any other issue, your first job is to inspect the exterior, fuel levels, and engine before hopping onto checking the transmission.

Now, to review the transmission, you’ll have to take it apart. If you see a stressed transmission, it will be a definite giveaway of why your tractor is pulling up on hills or retaining adequate speed.

Transmissions in John Deere tractors aren’t designed to replace fluids as they beget no fill cap or drain plug.

Thus, when the fluid’s viscosity levels are hampered, the transmission will fail to transfer any movement. In such cases, your only solution would be to go out and fetch a new transmission.

Setting it up is comparatively easier than having to deal with a non-consistent performing tractor.

John Deere D140 Starter Problems

You’ve tried everything, from trying to restart the tractor, pulling the started button, checking the battery power and electrical outlets.

But the tractor is still failing to start. Why?

To fix the puzzle, you will have to comprehend its location. One innovative and quick way of doing so is by utilizing a voltmeter. Here’s how to do it.

  1. Set your voltmeter to the DC setting and connect the wires to the negative tunnel of the battery and the positive side on the battery side of the solenoid starter.
  2. After anchoring the connecting wires, turn the key to check if the tractor starts.
  3. At this point, you need to check the voltmeter for any display on the screen.
  4. If you see no change in the reading, and a starter failure, here’s what you should do.

During these troubleshoots, sometimes working with a screwdriver works and starts the machine momentarily. However, it’s not viable to rely on a screwdriver every time you mow the lawn.

Therefore, your only reliable and safe alternative is to get your hands on a new John Deere transmission for this model.

Your tractor should start as ordinary once you’ve mounted it in place and connected all the surrounding parts and wires appropriately.

John Deere D140 Electrical Problems

Electrical issues in your John Deere tractor can spread out to starter dilemmas too.

Whereas the effects are similar, if you face no problem with the transmission, your next step would be to examine the electrical outlets.

Generally, the most significant electrical issue giveaway is the spark plug.

  • Now, to fix any issues in the spark plug, we have to begin with wiggling it free from both sides of the engine. You can also use pliers in this stage and a wrench to unclasp it.
  • Clean off any debris or dirt utilizing an emery board, sandpaper, or simply by your hands. Believe it or not, but even the scantiest amount of dirt on the spark plug could cause a blunder.
  • Place back the metal plug and remember to tighten it.

Moreover, if you notice that the spark plug is corroded or rusty, you will have to reinstate it with a new one. Spark plugs are cheap and can be found in any number of mechanical stores.

John Deere D140 Fuel Problems

Some persistent fuel disturbances agents are cracked fuel hose, troubled fuel pumps, or when the fuel has gone bad.

  1. For a cracked fuel hose, firstly, you need to purchase a new one. Take out the old, worn-out one and set up the latest.
  2. To install, work at the bottom of the hose to fit it in the valve cover. Once you’ve installed the open end at the base, the other end shouldn’t take long.

In other scenarios, it could be due to accumulated dirt in the bottom of the primary fuel, which creates a blockage for the fuel.

  1. To fix it, remove the hose and let the fuel flow freely.
  2. Wait till the gas comes out and reinstall the hose to the filter.
  3. Next, you need to blow air into the gas line to clear out the fuel line. Let the pressure release gradually and not all at once.

Lastly, if all your previous attempts go to vain, drain the existing fuel into a pan to check if your fuel has gone bad. Do the same if you face a similar problem with the John Deere X320 mower.

If the fuel gushes out fast, you’re all safe. If the fuel trickles down at an uneven pace, then this is where the problem had originated. Go ahead and replace the fuel if this is the cause.

This vlog correctly talks about its problems.


Lawn tractors are essential tools and the ultimate addition to your collection for maintaining a spotless and clean lawn.

While it relieves you from most lawn-related stress and work, this trustee and hardy equipment often endure generic wear and tear.

It’s a no-brainer that John Deere lawn tractors are the most reliable and sturdiest in the market.

We love that these tractors have meticulous attention to detail, leaving us with the perfect greenery rather than a scaly and sparse lawn.

However, our hearts leap out when John Deere D140 problems start getting the best of us. But now you know better.

Simply follow our outline, trace the error and fix it right at home. Owning hefty equipment has never been less intimidating, am I right?

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