John Deere 425 Problems

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The John Deere 425 riding mower is well-liked for its innovative design, reliability, maneuverability and dependability but it is not without problems. However, most of these problems can be easily solved.

Below are some of the Common John Deere 425 Problems:

  • Starting Problems
  • Transmission Problems
  • Problems When Running
  • Problems with the Electrical System
  • Engine Overheating
  • Excessive Vibration

7 Common John Deere 425 Problems and How to Fix Them


1. Starting Problems

If you find it difficult to start the engine of your John Deere 425 or it does not start at all, then the spark plug is possibly damaged or dirty. Learn more about why your John Deere mower won’t start.

Another cause for this problem is if the spark plug is not set correctly or the spark plug wires are loose or broken.

Apart from faulty spark plugs, your riding mower might not start because of a dirty filter, incorrect carburetor adjustment, faulty safety switch, and stale fuel.

Fix: Replace damaged or faulty spark plugs. You can also replace dirt fuel filters, change the damaged safety switch and adjust the carburetor idle mixture screw. 

Ensure that you drain stale gas and add a fresh one.

2. Transmission Problems


If your John Deere 425 model does not move forward or backward while the engine is operating, then the transmission is already faulty.

A common cause of this problem is broken or damaged traction drive belts or pulleys. These defective parts can affect the functionality and performance of the transmission.

Fix: Replace broken or damaged traction drive belts or pulleys. For proper mower operation, push the freewheel valve on your hydrostatic or automatic riding mower.

3. Problems When Running

Contaminated or stale fuel can make your riding lawn mower idle roughly or miss under a load. 

A defective or damaged spark plug or incorrect spark plug gap setting may be responsible for these issues. In addition, a clogged fuel filter can also cause uneven running.

Fix: Make sure that you replace stale or contaminated fuel with a new one. Furthermore, replace the clogged fuel filter with a new one.

4. Problems with the Electrical System

You might have problems with the electrical system of your riding mower while using it. These problems can be easily fixed. 

Here are some common electrical issues that you may face:

  • Starter Does Not Run

This issue might occur as a result of blown main fuse, corroded battery terminals, damaged starter, ignition switch problems, and low voltage battery.

Fix: Check for the blown main fuse and replace it. If you have an issue with corroded battery terminals, you should clean the contacts. 

Change the ignition switch, and repair or replace the damaged starter. For a low voltage battery, it is important to charge it.

  • Battery Doesn’t Charge

This electrical problem might happen as a result of defective battery cells or non-contact between the cable and the battery terminal.

Fix: It is advisable to change the mower battery if the battery cells are defective. 

If you notice that there is a non-contact between the cable and the battery terminal, ensure that you clean or replace the cable.

5. Engine Overheating

Your mower’s engine can overheat because of too much/little oil, excessive engine load, and low-quality engine oil.

Fix: To solve this problem, reduce the load if you observe that there is an excessive load on your John Deere 425 engine. 

Inspect oil level and change the oil if it is of low quality. Lastly, you can also check the internal bearing clearance of the mower.

6. Excessive Vibration

Your John Deere 425 riding lawn mower can vibrate excessively if the equipment drive belts are worn out. This problem might also occur because of worn traction drive belts and bent or unbalanced blades

Fix: If you want to fix this issue, you need to inspect and change worn-out equipment drive belts. 

In addition, check and replace the worn traction drive belt. It is also required that you replace defective blades.

7. Emits Black Smoke

Your John Deere 425 riding mower can emit black smoke because of clogged air filter elements, worn-out or damaged carburetor needle valve. Furthermore, a choke that is not fully engaged can also make the machine emit black smoke.

Fix: This problem can be easily solved. Simply clean or replace the plugged filter. Inspect and adjust the choke if it is not fully engaged. 

Lastly, check the carburetor needle valve and seat for wear and damage.


The John Deere 425 riding mower is well-known for its reliability and remarkable performance on lawns but it has some common issues.

We have discussed the issues of the John Deere 425 model and its troubleshooting tips to help solve the problem so that you can have a smooth mowing operation.

If you know that you do not have the expertise, time, or required tools to solve this problem, it is advisable to seek the help of a professional.

Frequently Asked Questions

How much does a John Deere 425 weigh?

The riding lawn mower weighs up to 805-900 pounds.

What engine is a John Deere 425?

It runs on a Kawasaki FD620D engine for a smooth mowing operation.

How long do John Deere riding mowers last?

With adequate care and maintenance, John Deere riding mowers can last for 1000 hours and even more.

Are John Deere mowers good?

Yes, they are one of the best lawn mowers out there. They are durable, reliable and can last long if well-maintained.