What Are The Common John Deere 797 Problems? Get the Solutions

John Deere 797 is a popular mid-mount Z-Trak or zero-turn mower used for commercial purposes. It offers a smooth ride and is capable of tackling tough terrain. Unfortunately, the John Deere 797 does have some issues that can affect performance.

What are the most common John Deere 797 problems? Many John Deere 797 Z-Turn owners experience hard starting, stalling, sputtering, uneven cuts, not cutting, producing a lot of smoke, and producing loud noises in the engine. Some issues have simple fixes, while others require more time and effort. 

But how do you know what the issue is? How do you troubleshoot and fix the problem? Read on to learn more about the most common problems and how to fix them.

Quick Overview Of The Most Common Problems For John Deere 797 and Quick Fixes

The table below gives you an overview of the common problems faced by many John Deere 797 owners and how to fix them. 

1Hard starting or not starting at allClean or replace the air filter
Test the battery
Check the spark plug
Test the starter solenoid, clean the carburetor
2Stalling, sputtering, or misfiringClean the fuel tank
Clean the air filter
Test the spark plugs 
Check the carburetor
Check for vapor lock
3Uneven cuts or not cuttingCheck the tire pressure
Check the deck leveling
Replace or sharpen the blades
Check for bent mower deck
Replace the worn out parts
4Producing a lot of smokeClean or replace the air filter
Check fuel injectors
Check piston rings
Check oil level
5Producing loud noises in engineCheck the oil pressure
Check the coil pack
Check the hydraulic system
Replace the worn out engine parts

5 Most Common John Deere 797 Problems

Let’s examine the 5 most common problems, their possible causes, and the best solutions. 

1. John Deere 797 Hard Starting or Not Starting At All

You’re ready to tackle the long day on the field with your John Deere 797 tractor, and it won’t start suddenly. Or, maybe it will start, but it is hard to get going. 

Here are a few potential causes:

  • Clogged Fuel Filter: The air filter cleans the air entering the engine, and when clogged too much, your engine will not only try starting lean, but it might not start at all.
  • Dead Battery: The battery is responsible of providing enough power to start the mower. So, if dead or too low, your engine won’t or will take time to start. 
  • Bad Spark Plug: The spark plug ignites the fuel in the combustion chamber, providing power to start the engine. If there is no spark or a weak spark, it won’t ignite the fuel mixture.
  • Faulty Starter Solenoid: The starter solenoid supplies power to start the engine when you turn the key in your ignition switch. A faulty starter solenoid can prevent your mower from starting altogether.
  • Carburetor Issues: A dirty carburetor can cause poor performance, and a clogged one will prevent the engine from starting altogether.


  • Remove the air filter and check for any dirt build-up. If you find it clogged, replace it with a new one.
  • Use a multimeter to test your battery. If it is below the manufacturer-recommended voltage, replace or recharge the battery. You could try charging it to see if it works, but you might need a new one.
  • Check the spark plug for any dirt or signs of carbon build-up and replace it if necessary.
  • Test the starter solenoid to see if it’s working correctly. Inspect the starter solenoid for broken wires or corrosion, and replace it if needed.
  • Clean the carburetor to ensure proper fuel flow. Use the manufacturer’s recommended cleaning solution and follow their directions carefully.

2. John Deere 797 Stalling, Sputtering, or Misfiring

Another common problem most John Deere 797 owners face is the mower stalling, misfiring, or sputtering. While low fuel can cause the engine to hesitate, most people will associate it with stalling; however, that not be the reason. 

Here are a couple of reasons for this:

  • Dirty Fuel Tank: A dirty fuel tank is one of the most common reasons for stalling or misfiring in a John Deere 797. Over time, dirt, debris, and other contaminants can accumulate and cause the engine to run poorly or stall completely.
  • Faulty Spark Plug: It could also be a faulty spark plug. They ignite the air-fuel mixture in the engine’s combustion chamber. If it fails to do so, it can cause the engine to run poorly or not start at all.
  • Clogged Air Filter: A clogged air filter restricts airflow into the engine and causes it to run poorly.
  • Faulty Carburetor: The auto-sensing carburetor on the John Deere 797 can sometimes malfunction, causing the engine to cut out after running for a certain period.
  • Vapor lock: Another potential cause of stalling, misfiring, or sputtering in a John Deere 797 is the vapor lock. 

Vapor lock occurs when liquid fuel in the fuel delivery system changes state to a gas. This disrupts the fuel flow to the engine and causes it to stall or run poorly. It can be caused by several factors, including high temperatures and low fuel levels, can cause this.


  • Inspect the mower’s fuel tank. If dirty, clean it out thoroughly to remove any debris or contaminants causing the engine to run poorly.
  • Remove and clean the air filter. If it’s beyond cleaning, replace it with a new one.
  • Remove and check the spark plugs for carbon deposits and corrosion. If it’s black or the gap is too large, replace it.
  • Check the carburetor for any blockages or clogs. If needed, clean it with a can of carburetor cleaner.
  • Check the fuel delivery system for signs of vapor lock, such as air bubbles in the fuel lines. If found, replace the fuel cap, and if possible, move the mower to a cooler location. Try filling up your fuel tank more frequently and avoiding high-temperature areas when possible.

3. John Deere 797 Making Uneven Cuts or Not Cutting

If you’re experiencing uneven cuts or your John Deere 797 is not cutting, there could be several reasons. 

Here are the top five reasons why this might be happening:

  • Uneven Tire Pressure: It might surprise many, but uneven tire pressure can cause one side of the mower deck to be higher, resulting in rough cuts.
  • Improper Deck Leveling: Your JD Zero turn will make uneven cuts if your mower deck is not leveled correctly.
  • Dull Blades: Dull blades can also cause uneven cuts as they won’t be able to cut the grass evenly.
  • Bent Mower Deck: A bent mower deck is one of the most common reasons for uneven cuts. This can happen due to various reasons, such as hitting a rock or stump while mowing or simply due to wear and tear over time.
  • Worn-Out Parts: Worn-out parts such as belts or pulleys can also cause uneven cuts or prevent the mower from cutting.


  • Check your JD 797 tire pressure. If there is any low-pressure tire, inflate it to ensure the mower is even on both sides.
  • Check your mower deck level and adjust it according to the manufacturer’s recommendation.
  • Inspect your blades and happen them if they’re dull. If they’re too worn out, replace them.
  • Check for signs of a bent mower deck. You can try to press it back into place, but replace it if it’s too badly damaged.
  • Inspect all parts of your mower and replace any worn-out parts.

4. John Deere 797 Producing A Lot Of Smoke

If your John Deere 797 produces a lot of smoke, it could be that your mower is running rich or lean. It could also mean it is burning oil, something that should be happening.

Here are some of the most common causes:

  • Dirty Air Filter: When your JD 797 air filter is dirty it will restrict the air flowing to the engine. This will cause it to run rich and produce more smoke than usual. The result is a lot of black smoke.
  • Faulty Fuel Injectors: Faulty fuel injectors can cause an uneven fuel spray pattern, leading to incomplete combustion and excessive smoke production. Get your fuel injectors checked and replaced if necessary.
  • Worn Piston Rings: Worn piston rings can allow oil to seep into the combustion chamber, causing the mower to produce more smoke than usual.
  • Overfilled Oil Level: Overfilled oil can cause excessive pressure in the crankcase, leading to oil leaks and increased smoke production.


  • Inspect and clean the air filters. If it’s too dirty, replace it with a new one.
  • Check the fuel injectors and replace them if necessary.
  • Inspect the piston rings and replace them if they are worn out.
  • If the oil level is too high, drain until it reaches the recommended level.

5. John Deere 797 Producing Loud Noises In The Engine

If you own a John Deere 797 mower and have noticed that it produces loud noises in the engine, there could be several reasons for this issue. 

Here are some of the possible causes:

  • Low Oil Pressure: Low oil pressure is among the most common reasons for loud engine noises. If your mower’s oil level is low or the oil pump is not working correctly, it can cause the engine to produce loud knocking or ticking sounds.
  • Faulty Ignition Coil Pack: If the coil pack is not functioning correctly, it can cause misfires and rough running, resulting in loud engine noises.
  • Hydraulic Issues: A problem with the hydraulic system, such as low fluid levels or a clogged filter, can cause the engine to produce unusual sounds.
  • Worn-Out Engine Parts: Over time, certain parts of your mower’s engine may wear out and need to be replaced. Worn-out bearings or pistons can cause loud knocking sounds in the machine.


  • Check the oil level. If it’s low, add more oil and see if the noise disappears. If not, the oil pump must be inspected, repaired, or replaced.
  • Inspect the ignition coil pack for any signs of damage or wear. If it’s faulty, replace it with a new one.
  • Check the hydraulic system for any issues. If there are low fluid levels or a clogged filter, address these problems immediately.
  • If the engine parts are worn out, they must be replaced to eliminate the loud noises. Have a professional mechanic inspect and replace any damaged parts.


Owing a John Deere 797 Z-Turn mower can be a great experience, but it can also be a source of frustration if you encounter any issues. The five most common problems are hard starting, stalling, sputtering, uneven cuts, and producing loud noises in the engine.

Each issue has simple fixes, but some may require more time and effort. The best thing to do is to ensure all preventive maintenance is done and the machine is in good condition. Follow the manufacturer’s guidelines and troubleshoot any issues if they arise.

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