4 Common John Deere D140 Problems (360 Guidelines)

Have you been hearing different issues about the John Deere D140 tractor lately? Well, there’s no doubt about the brand, but it’s true the D140 model shows some malfunctions at times. 

John Deere D140 problems are related to electrical issues, engine problems, mower machine problems, and transmission issues. Most of these problems occur due to poor setup, insufficient fuel, and damaged or worn-out components. Usually, by changing or adjusting the components, you’ll be able to solve the problems easily.

John Deere D140 Issues
Source: Tractors Specification

Check out all the common problems and their solutions of the John Deere D140 by reading this article till the end.  

John Deere D140 Engine Problems

Problems  Reasons Solutions
Engine starting problems
  • Clogged fuel lines
  • Improper gasoline
  • Worn-out spark plugs
  • Carburetor issues
  • Damaged electrical wires 
  • Clean the fuel lines.
  • Replace stale fuel with fresh ones.
  • Test ignition spark.
  • Investigate wire connections and replace the corroded wires.
  • Fix the carburetor. 
Engine running rough
  • Corroded electrical connections.
  • Dirty cooling fins and air filter
  • Choke cable sticking
  • Defective ignition setup
  • Replace the faulty wire connections.
  • Clean the cooling fins and change the air filter.
  • Check the choke cable and repair it.
  • Adjust the ignition system correctly.  
Overheating issues 
  • Overloaded engine 
  • Improper engine oil level.
  • Low-quality oil
  • Clogged engine components
  • Lower voltage power.
  • Keep an adequate amount of engine oil.
  • Replace stale oil with fresh one.
  • Clean all the engine components properly. 

Problem 1: Hard-to-Start Engine

The most common scenario with John Deere D140 engine issues is that it doesn’t start at all. Sometimes, it starts, but it takes an annoying amount of time to start the engine.   


There are 5 distinctive reasons responsible for John Deere D140 engine starting issues.

These reasons include a clogged fuel system, stale gas, faulty spark plugs, a damaged carburetor, and an electrical system. You might notice this problem even if the throttle or other engine parts wear out over time.

John Deere D140 Issues Hard to Start Engine
Source: Green Tractor Talk


To ensure a good engine start, you have to take care of the engine components properly. Here is a list of actions you can take to solve the engine starting problem.

  • First, you have to check the fuel tank. If the fuel tank is empty, you have to fill it up with high-quality fresh gasoline. 
  • Then, check whether the fuel lines are clogged. Try to remove all the dirt and debris from the fuel filter and lines. But if it’s not cleanable, you should change the filter and fit a new one. 
  • After that, you should inspect all the electrical wire connections. 
  • Test all the spark plugs and see if they work. If you find any damaged spark plug, replace it immediately.
  • Finally, diagnose the carburetor and fix it with the help of a professional. 

Well, now that you started the engine, it’s possible you could see it running rough after multiple uses. 

Problem 2: Unstable Engine Operations

Sometimes, John Deere D140 engines don’t run as expected as it’s unable to use the fuel properly to operate the ignition system.     


There are 4 reasons which inhibit engine operations. For example, when the cooling fins and air filters become filthy, the engine won’t be able to run properly.

Again, the engine will become unstable if the ignition is not correctly set up. Faulty electrical connections are also responsible for unsteady engine operations. 


For each reason, you have to apply separate tactics to solve this issue. Take a look at the following quick fixes to help you run the John Deere D140 engine.

  • Take the plugged cooling fins and air filter out and wash them thoroughly.
  • Inspect all the electrical cable connections and repair or replace them if you find them damaged.
  • Diagnose the damaged choke cable and repair it.
  • Set up the ignition system correctly by adjusting the misplaced wiring. 

Applying most of the above points will finally make the engine run smoothly.   

Problem 3: Engine Emits Too Much Heat

John Deere D140 engine overheats from time to time. It’s a common problem when the engine is taking too much load than its capacity. 


The overheating issue arises for several reasons. First of all, it happens when the engine has become overloaded with power capacity (22 HP).

Again, poor-quality fuel oil is also responsible for the engine to get hot faster. Also, when the engine oil is not at the appropriate level, it causes issues for the John Deere D140 engine.  


Whenever you need to calm down the engine, you can apply the following instructions:

  • Decrease the engine load so that it doesn’t overload the engine.
  • If the engine oil is too high than its required level, drain some oil. On the contrary, if the engine oil is low, you should add more oil. 
  • Make sure all the clogged components are cleaned. 

John Deere D140 Electrical Problems

Problems  Reasons Solutions
Starter motor fails to turn on the engine
  • Damaged battery
  • Ignition switch issues
  • Faulty Starter
  • Blown fuse and corroded wiring system
  • Charge battery and ensure clean terminals.
  • Replace the lock of the ignition switch.
  • Repair the starter or replace it with a new one.
  • Install new fuse and wiring system.
Battery doesn’t charge
  • Problematic battery cells
  • Poor connection between the wires and battery poles
  • Install a new battery
  • Diagnose the battery connection and clean between the cables and battery pole.  

Problem 1: The Starter motor can’t Turn on the Engine

The John Deere D140 also has starter motor problems that lead to faulty engine operations. The main culprit is the battery, starter motor, and wiring system. 


If the battery cords are damaged, the JD D140 won’t be able to power up the engine. A weak battery is also responsible for the same issue.

Again, the engine can’t function properly when the ignition switch has issues. Common electrical problems like a blown fuse, disconnected wiring system, and problems with the starter inhibit the engine from starting. 


You should take the following measures to solve this electrical issue in your John Deere D140 tractor:

  • Install a fresh fuse if the old fuse has blown out.
  • Inspect all the battery terminals and check if there’s any corrosion. Replace the terminals if they are damaged.
  • Replace the ignition lock if the ignition switch is problematic.
  • Repair or replace the starter immediately if it is damaged.
  • Change the wiring system when the wiring is faulty.

Problem 2: Battery Unable to Charge

Many times, you’ll see the battery of the John Deere D140 is not charging. This is an alarming electrical issue.

John Deere D140 Battery Unable to Charge
Source: YouTube


The main reason the battery doesn’t charge is because of corroded battery cells. Moreover, a faulty cable connection will stop signaling the battery. Hence, the battery can’t charge the tractor.


If this is the situation for you, you have to install a new battery. Inspect the contact between cables and battery poles. If they’re dirty, clean them thoroughly.  As a result, you’ll be able to fix this problem. 

John Deere D140 Transmission Problems

Problems  Reasons Solutions
Noise coming from hydrostatic transmission
  • The speed control linkage has worn out
  • Overload transmission system
  • Clogged fluid or insufficient fuel level
  • Damaged transmission parts
  • Repair or adjust the linkage
  • Decrease transmission load
  • Replace the clogged fluid and fill the fuel tank to the required level.
  • Repair or replace the defective parts.
Shifting Issues
  • Gshift and the hydrostatic pump have expired.
  • Misadjusted transmission shifts control components 
  • Replace the G Shift and hydrostatic pump.
  • Adjust or replace the transmission shift control elements 
Low power
  • Insufficient fluid level 
  • Worn-out drive sheave
  • Broken or misadjusted shift linkage
  • Bent speed control pedal linkage
  • Add extra fluid to level up the transmission housing
  • Replace the sheave with a new sheave
  • Change the shift linkage 
  • Replace or adjust the linkage.

Problem 1: John Deere D140 Hydrostatic Transmission Problems

You might experience the tractor moving slower than the usual speed. You’ll also notice that it’s hard to push the JD D140 up the hill. All these happen because of transmission problems. 


The reasons for hydrostatic transmission making noise include worn-out linkage, overload transmission, insufficient or dirty fluid level, and damaged transmission components. 


By applying some simple fixes, you can get rid of the transmission noise. Here’s what you have to do.

  • If the linkage or transmission components are damaged or worn out, you must repair them if possible. It’s better to replace them if they’re fully worn out.
  • Add fresh fluid to the fuel tank and make sure it matches up to the required level.
  • If you notice the transmission lines got overloaded, reduce some load.  

Problem 2: Hard to Shift

Sometimes it’s difficult to shift the John Deere D140 gear. As a result, you’ll face a steering problem. This happens for 2 simple reasons.


The first reason might be the G Shift or hydrostatic pump has worn out. Again, it might happen due to poor transmission component setup. 


To solve this issue, you have to repair the g shift or hydrostatic pump based on the problem. In case, both of them wear out, you have to replace them with new components. 

Again, if you notice the transmission setup is a mess, you have to readjust the components. This will solve the steering issue. 

Problem 3: Low Transmission Power

When you’re running the tractor, you might notice it’s unable to climb the hills like before. And it happens because the power transmission is low for some reason. 


This type of situation occurs when the fluid level is low or the drive sheave is defective or worn out. Another reason could be your tractor’s shift linkage is not properly adjusted or it got damaged.

Similarly, if the speed control pedal linkage is bent and poorly adjusted, the tractor will have low transmission power.  


So, to solve this problem, you have to inspect the drive sheave, shift linkage and speed control pedal linkage properly.

If the components are repairable, repair them immediately. But if they’re worn out, you must change them. Moreover, keep an eye on the fluid level and add more fluid if there’s a shortage. 

John Deere D140 Machine Problems

Problems  Reasons Solutions
Excessive vibration
  • Worn-out attachment driven belt and traction drive belt
  • Unbalanced cutting blade
  • Diagnose the belts and replace them with new belts.
  • Change the blades if needed
Tractor can’t move with engine running
  • The parking brake limits the tractor moving
  • Loose mower blades
  • Engaged bypass valve lever
  • Unbalanced blade
  • Insufficient transmission oil
  • Loosen the parking brake
  • Make the bypass valve lever tight.
  • Disengage the bypass valve lever
  • Adjust the blade to a correct balance.

Problem 1: Excessive Tractor Vibration

Another common problem lawnmowers face is that the tractor vibrates more than the usual amount. You can detect it by noticing the blades losing balance while cutting.


Worn-out tractor components like attachment-driven belts and traction-driven belts are the culprit for this problem.

If the attachment-driven belt and traction drive belt wear off, the tractor begins to vibrate incessantly. You should also diagnose the cutting blades. Damaged blades can be responsible for the vibration too. 


To minimize the vibration, first, you have to diagnose the attachment and traction-driven belts. If they’re completely damaged, install new belts. 

Still, if you’re facing the same problem, replace the cutting blades. This is effective when the blade is bent or unbalanced. 

Problem 2: Engine Running But Tractor not Moving

A running engine doesn’t always mean the tractor is capable of moving or operating properly. The tractor will not move if there are internal tractor problems. 


By internal problems, I meant problems regarding parking brakes, bypass valve levers, mower blades, and transmission fluid. If the parking brake is blocking the tractor from functioning, the tractor won’t move. 

Moreover, an engaged bypass valve lever is also responsible for it. You should also check transmission oil if it’s filled to the required amount or not. Lastly, loose mower blades also halt the operation of the John Deere D140. 


In order to mitigate this issue, first, you have to release the parking brake and disengage the bypass valve lever.

Then, check the transmission fluid level. If it’s lower than the required amount, pour some fresh oil and ensure the tractor is moving. 

Finally, you should tighten any loose mower blades and correct the balancing. All of these actions will help the tractor move. 


How Long Will John Deere D140 Last?

On average, John Deere D140 lasts for 8 to 10 years. It’s roughly about 4,500 to 5,000 hours of mowing the tractor can give you. After that, the tractor starts wearing out and it’ll stop working.

What Engine Is in John Deere D140?

The John Deere D140 uses a 655cc, 2-cylinder air-cooled gasoline engine that fuels up by 22 HP.. It contains an air cleaner cartridge and an electric starter. The intake and exhaust valve clearance is nearly 0.005 inches. 

Can You Mix Old Gas with New Gas for Lawnmower?

No, you can’t mix old gas with new gas for a lawn mower. It’s because the old gas goes stale and loses combustion power. When the new gas is mixed with the old gas, the new gas will also lose its combustibility. As a result, the engine won’t fire up.  

Final Words

So, that’s it! These are all the John Deere D140 problems you might encounter. With the help of this article, hopefully, you’ll be able to solve.

Make sure you take care of the tractor and maintain it regularly. It’ll help facing issues on a regular basis. Best of luck with your tractor. 

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