John Deere Z960R Problems: What Are The Causes And How To Fix?

Like any other vehicle, the John Deere Z960R isn’t also free from drawbacks. Though it has the excellent mowing capability, the owners will encounter several issues over time.

So, what are the john deere Z960R problems? Usually, backfiring, misfiring, poor fuel economy, starter problems, and black smoke from the exhaust are pretty common problems. You may also encounter rattling noise, overheating, and engine power loss.

In this article, we will provide you with a list of common problems in this John Deere model. You will learn their causes and solutions after reading this article. So, keep reading!

Table: Several Common Problems In John Deere Z960R with Quick Solutions

Below are some of the most common problems and their solutions to the John Deere Z960R. 

No.Problems Solutions 
1Overheating engineClean the clogged air filter and cooling fin
Maintain appropriate oil level
2Backfire or misfires Clean and repair the dirty or faulty spark plug, air filter, and fuel injector 
Fix the tappet adjustment 
3Black smoke coming from the exhaust Fix or change the defective air filter
Repair the leakage of the oil tank
4Poor fuel economy Install sharp cutting blades
Use appropriate oil grade
Clean the air filter
5Starter Problems Check the battery and ensure proper connection
Change the blown fuses
6Rattling noisesRepair and clean the damaged drive belt 
Readjust the blades’ alignment
7Reducing engine performance Don’t operate too fast
Use appropriate fuel
Reduce the fuel-to-air ratio in the engine 

7 Most Common John Deere Z960R Problems 

We will provide you with the causes and solutions of the seven most common problems of the JD Z960R mower. Let’s see how to fix those problems in detail:

1. Overheating Engine

Usually, this problem occurs when the engine is unable to release its heat due to malfunctioning of the cooling system. Consequently, excessive overheating can damage the engine. 

Sometimes the air intake valve of the cooling fin may get clogged with grasses. This will prevent the circulation of cooling air toward the engine. 

Moreover, if the engine runs with an inappropriate oil level, it will also overheat the engine. Oftentimes, operating the mower for too long also causes this issue.


  • Clean the dirty and clogged air filter. You should replace the filter if it gets damaged
  • You need to check the cooling fin to see if it’s clogged with grass. If you find it clogged, clean them
  • Make sure the engine oil isn’t too high or too low. Fill or drain the oil to reach an appropriate level
  • Don’t operate your mower for too long. Give some break in the middle 

2. Backfire Or Misfire

Misfire and backfiring of John Deere Z960R usually indicate issues with the spark plug. When misfiring occurs, it may stop the tractor, cause sluggish movement, or can cause backfiring. 

Misfire and backfire may occur due to a faulty spark plug or injector. Because of these, the fuel ignition will occur in irregular intervals. Besides, the throttle will decrease if you stop the mower or lower its speed suddenly. 

As a result, the air-fuel mixture will become lean, and the presence of excess air will cause complete combustion. Thus, the engine will backfire in this case.


  • Check and clean the dirt from clogging the spark plug, ignition plug, and injector nozzle 
  • If the spark plug and ignition plug are defective, install new ones
  • Lower the speed or stop the mower gradually
  • Fix the tappet adjustment to adjust the valve quickly with the decreasing RPM

3. Black Smoke Coming From The Exhaust

When you notice that black smoke is coming from the exhaust; indeed, there is an issue in the fuel consumption ratio. Typically, this indicates that your mower’s engine is burning excessive fuel. 

If the air filter is faulty or clogged, it will become unable to supply adequate air to the engine. Also, leakage in the oil tank can be the reason for excess oil in the engine. The extra fuel in the engine will result in black smoke from the exhaust.


  • Clean the blocked air filter and also replace it if it is already damaged
  • Repair or replace the cracked or leaking oil tank

4. Poor Fuel Economy

Generally, at starting, the John Deere Z960R will serve excellent fuel economy. But over time, fuel consumption will increase. This mainly happens due to the aging of mower components. For example, if the blades become dull, your mower will go through extra strain for cutting the grass, this happens. 

Also, low-quality oil won’t be able to provide adequate lubrication in the engine. Thus, the engine will overwork, which will require extra fuel consumption. Moreover, faulty air filters or spark plugs can be the reason for poor fuel economy.


  • Change the dull blades with sharp ones
  • Use oil of the grade that the manufacturers recommend
  • Replace the faulty air filter and spark plug 

5. Starter Problems 

Sometimes, the starter may not work, and it will fail to turn the mower’s engine also. These problems may occur due to a dead battery or loose connections with battery terminals. Corrosion on those terminals can be the reason for the loose connections.

Also, a blown fuse will induce a break in the overall circuit, which will cause the starter issue. Besides, defective key switches and engaged mowers can also be responsible for this issue. 

You should check this YouTube video to understand this starter problem better.


  • If the battery is dead, you need to replace it with a new one
  • Check the battery terminals for corrosion and solve the corrosion issue
  • Make sure the battery has enough charge
  • Change the blown fuse and install a new one
  • Repair or change the faulty key switch
  • Disengage the mower

6. Rattling Noises

This problem may come with the vibration of the John Deere Z960R. Generally, if internal parts become loose somehow, it may cause this noise issue. Also, bent blades may rub with any other mower parts, causing an unpleasant rattling noise.

Moreover, when the attachment and traction drive belt becomes damaged, there will be a lack of significant tension on the belt. These loose belts are pretty prone to cause a rattling noise. Besides, dirty pulleys might also cause a rattling noise.


  • Repair or change the worn-out traction and attachment drive belts
  • Readjust the blades’ alignment of your mower
  • Replace the bend blades
  • Clean the dirty pulleys

7. Reducing Engine Performance

Sometimes, while mowing, your mower may lose its power and can become stall. Engine overheating can be responsible for this. Also, clogged blades, air filters, and spark plugs might be the main issue here.

Excessive fuel inside the engine and air filter may also result in this issue. Sometimes, using inappropriate fuel will overwork the engine. Due to this overworking, the engine performance will also reduce.


  • Clean the clogged blades, air filter, and spark plug
  • Repair the leakage in the oil tank
  • Replace the fuel with a suitable fuel for your mower
  • Keep the mower speed within the required level 


You shouldn’t let the problems of John Deere Z960R linger if you don’t want them to damage the mower’s engine.  Indeed, all minor issues like rattling noise and reduced performance are not concerning. But you still shouldn’t let them remain unfixed for an extended period.

On the other hand, problems like engine overheating, excessive fuel consumption, and black smoke from the exhaust are alarming. Make sure to fix them quickly to prevent ultimate engine failure.

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