No matter what brand of lawn mower you have, when you own it long enough, you will run into problems that will need to be repaired to ensure your mower keeps operating at its best. The same is true of John Deere lawn mowers.
John Deere has a strong reputation in the equipment industry, but just like other manufacturers, their equipment doesn’t last forever without issues developing along the way.
I have put together a list of issues common to running lawn mowers and how to solve these issues. You will find links that provide more in-depth information on each problem including troubleshooting steps.
The most common John Deere lawn mower problems are:
- John Deere doesn’t start
- John Deere dies while mowing
- John Deere is smoking
- John Deere has a weak hydrostatic transmission
- John Deere won’t drive straight or steer correctly
- John Deere won’t move
- John Deere is shaking or vibrating
- John Deere is cutting uneven
- John Deere is leaking gas
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Follow all safety instructions provided in your equipment operator’s manual prior to diagnosing, repairing, or operating.Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
10 Common John Deere Problems & Solutions
John Deere Mower Problem 1: Mower Won’t Start
When your John Deere mower won’t start, look at items that can cause an air or fuel restriction. Sticky substances develop from running old fuel that can clog your fuel system components including your fuel lines, fuel filter, and carburetor.
Making sure you run the correct gas through your John Deere and properly care for your fuel will help prevent starting issues due to fuel.
Other items to check on your John Deere include the battery, safety switches, and charging systems. A charging system that fails to keep your battery charged will prevent your mower from starting. Electrical components that don’t work right can also contribute to the problem.
Detailed information can be found at:
Reasons Your John Deere Mower Won’t Start
| Cause | Reason for Problem | Solution |
| No gas in the fuel tank | Fuel tank is empty | Fill with fresh fuel |
| Bad or old fuel | Fuel breaks down overtime making your fuel less efficient and prone to clogging the fuel system | Drain the fuel tank and fill it with fresh fuel. Use a fuel additive like Sea Foam to stabilize the fuel and assist with cleaning the fuel system. Use the right fuel. |
| Faulty or clogged fuel cap | The vent in the cap can get clogged causing your tank to form a vacuum restricting fuel flow | Use a thin piece of wire to try to clear the clogged vent. Replace the cap if needed. |
| Bad spark plug | Excessively dirty or broken spark plug; bad connection; not gapped correctly | Replace with a new spark plug, secure connections, and ensure it is gapped to manufacturer specifications |
| Plugged air filter | Dirt and grass can plug the air filter preventing airflow | Remove the filter and clean it. Replace the filter if it is in bad condition. |
| Plugged fuel filter | A dirty fuel filter will restrict fuel flow | Replace the fuel filter |
| Bad fuel pump | A failed or leaking fuel pump will no longer create the pressure needed to pump fuel | Replace the fuel pump |
| Blocked fuel lines | Bad fuel deposits and dirt can build up and clog the fuel lines preventing the engine from getting the required fuel | Use a carb cleaner and compressed air to clear the clog out of the fuel line. Replace the line if necessary. |
| Dirty carburetor | The carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flow | Clean the components making up the carburetor. Replace if needed. |
| Bad battery or loose & dirty terminals | A dead battery, loose cables, or corroded terminals can cause starting problems | Charge your battery and replace it if it won’t hold a charge. Make sure your cables are tight and clean the corrosion from terminals. |
| Bad safety switch | Safety switches are a safety measure that exists to prevent your mower from starting in certain situations. When a switch fails, your mower may not start. | Test and replace faulty safety switch |
| Bad ignition switch or coil | Your mower will not start when either the ignition switch or coil is bad | Test and replace a bad switch |
| Broken recoil | A pull start mower may have a damaged or broken recoil preventing the recoil to initiate starting your engine | Check the recoil to see if it can be restrung or if broken parts, like the pulley, can be replaced. Replace the recoil assembly if needed. |
John Deere Mower Problem 2: Mower Starts and Dies
Many of the same reasons that cause your mower not to start can cause your John Deere to lose power and die.
When your mower isn’t able to get the right amount of fuel and air it needs to run efficiently, it can begin to run sluggishly and possibly shut down. Check all items of your fuel and air systems for restrictions.
Overheating can cause your John Deere to die. It’s important to use the correct engine oil; maintain the correct engine oil levels, and clean out your engine cooling fins and around the engine so air can circulate around your engine to keep it cool. Find out more about overheating here.
Your electrical system or clogged mower deck can also cause your mower to die after it has been running.
Detailed information can be found at:
Why Your John Deere Mower Starts Then Dies
| Cause | Reason for Problem | Solution |
| Bad fuel | Fuel breaks down overtime making your fuel less efficient and prone to clogging the fuel system and engine damage | Drain the fuel tank and fill it with fresh fuel. Use a fuel additive like Sea Foam to stabilize the fuel and assist with cleaning the fuel system |
| Plugged air filter | Dirt and grass can plug the air filter preventing airflow | Remove the filter and clean it. Replace the filter if it is in bad condition. |
| Dirty or broken cooling fins | Cooling fins get packed with dirt, oil, and grass not allowing air to effectively cool the engine block | Replace broken fins and clean the cooling fins. |
| Clogged fuel lines or filter | Bad fuel deposits and dirt can build up and clog the fuel lines preventing the engine from getting the required fuel | Use a carb cleaner and compressed air to clear the clog out of the fuel line. Replace a plugged fuel filter. |
| Dirty carburetor | The carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flow | Clean all components making up the carburetor. Replace if needed. |
| Too Much Engine Oil | Too much engine oil increases pressure in the crankcase causing it to overheat and die | Correct your engine oil level by removing a little oil |
| Bad Spark Plug | Dirty or damaged spark plug causes the plug to foul out and cause intermittent running problems. | Clean or replace spark plugs if needed. Ensure spark plug wires are securely attached and the plug is gapped correctly. |
| Faulty Ignition Coil | A windings on the coil can separate and short out a bad ignition coil | Check for a break in the continuity using an ohm meter and replace is found bad |
| Choke is in the Wrong Position | A choke is used for cold starts. The choke can cause your engine to shut off when it continues to restrict airflow after the engine warms. | Make sure the choke is in the correct position |
| Bad Gas Cap | Gas caps have vents for air to pass through. When the vents get plugged, the fuel tank will cause fuel restrictions. | Replace a fuel cap that no longer vents |
| Clogged Mower Deck | A clogged mower deck causes a strain on the engine causing it to work hard and possibly shut down | Periodically scrape your mower deck to keep it clean |
John Deere Mower Problem 3: Lawn Mower Smokes
Something as simple as a plugged air filter can cause your John Deere to smoke. Smoke is often created when your mower is running rich emitting black smoke because it is running a higher ratio of fuel to air.
It can also be created when oil is burning off due to oil in the cylinder or possibly from an oil leak onto a hot muffler.
Detailed information can be found at:
Why Your John Deere Lawn Mower is Smoking
| Cause | Reason for Problem | Solution |
| Plugged air filter | Dirt and grass can plug the air filter preventing airflow | Remove the filter and clean it. Replace the filter if it is in bad condition. |
| Too much oil in the crankcase | Excessive oil can cause pressure to build in the engine allowing oil to get into the cylinder through the valve train | Drain a little engine oil until it is at the manufacturer’s recommended oil level. |
| Engine oil level is too low | Lack of oil can increase friction in your engine causing extreme heat. | Bring to a small engine repair shop to inspect engine damage. You can try adding oil, but it is often too late to this fix your engine problem. |
| Internal problems including the piston ring, valve train or engine gasket | Internal engine problems can have a detrimental effect on your mower if they are not caught soon enough and fixed. | Bring your John Deere to your local small engine repair shop for troubleshooting |
John Deere Mower Problem 4: Weak Hydrostatic Transmission
| Cause | Reason for Problem | Solution |
| Bad drive belt | A bad drive belt can cause your pump not to work efficiently | Replace a frayed, cracked, or worn belt |
| Bad tensioner pulley | When a tensioner pulley fails, it fails to keep tension on the drive belt | Replace the pulley and grease the tensioner arm |
| Low or old hydraulic oil | Low or old hydraulic oil can fail to lubricate the hydraulic system causing your hydraulic system to seem weak | Change your hydraulic oil at regular intervals as recommended by John Deere. Check your hydraulic oil periodically to ensure your hydraulic fluid is full. (Some transmission systems are sealed and they can’t be serviced. If you are having trouble with a sealed system, see your dealer). |
John Deere Mower Problem 5: Mower Won’t Drive Straight or Steer Correctly
It can get frustrating when you are always having to adjust the operation of your mower because it is pulling to the right or left. Here is a list of items to check on a zero-turn or riding lawn mower to make the necessary corrections to get your mower to drive straight.
| Cause | Reason for Problem | Solution |
| Incorrect tire pressure | Unequal tire pressure can cause your mower to pull to one side. | Check tire pressures and keep them filled to the manufacturer’s spec. Tires on each side of your mower require equal pressure. |
| Bad dampers on zero turn | Bad dampers will cause your mower to jerk to one side when moving forward | Replace with a new damper |
| Tracking adjustment needed on zero turn | When one tire is moving faster than the other, your mower can pull to one side | Adjust the speed adjustment bolt to change the rotation speed of the tire. Refer to your owner’s manual. |
| Worn or loose steering components in riding mower | Worn bushings, washers, and gears can cause your mower to not steer one way or the other | Inspect and replace the parts that failed on your steering system |
John Deere Mower Problem 6: Lawn Mower Won’t Move
Detailed information can be found at:
9 Reasons a John Deere Zero Turn Won’t Move or Go Forward
| Cause | Reason for Problem | Solution |
| Drive release lever in the wrong position | The drive release lever allows hydrostatic mowers to roll freely | The drive release lever must be in the operating position. |
| Missing key in the axle | Your riding mower may have a small key in the axle that may have fallen out of place | Replace the key in the axle |
| Drive pump belt is worn | The mower won’t move if your drive belt has fallen off. It could also not move if the belt is worn. | Replace a worn or cracked belt. Make sure the belt is securely around the pulleys. |
| Bad tensioner pulley | The bearing in the tensioner pulley can fail | Replace the tensioner pulley |
| Missing idler arm spring | If the idler arm spring breaks or goes missing, it can no longer place tension on the drive belt | Replace the broken or missing spring |
| Low or old hydraulic oil | Low or old hydraulic oil can fail to lubricate the hydraulic system causing your hydraulic system to seem weak | Change your hydraulic oil at regular intervals as recommended by John Deere. Check your hydraulic oil periodically to ensure your hydraulic fluid is full. (Some transmission systems are sealed and they can’t be serviced. If you are having trouble with a sealed system, see your dealer). |
| Hot hydraulic fluid | Hot hydraulic fluid can be a sign of damage to your hydrostatic transmission system | Let your hydraulic oil cool. If you find your mower runs fine when it is cold, but becomes weak when the hydraulic system gets hot, have your mower checked at your local John Deere dealership. |
| Air in the hydraulic system | Air must be bled from the hydraulic system after changing your hydraulic fluid or the mower will not be able to move at normal speeds | Follow John Deere’s procedures for changing the hydraulic fluid and bleeding air from the system in your owner’s manual. |
John Deere Mower Problem 7: Mower is Vibrating
Something as small as a pebble or acorn can cause your mower to excessively vibrate. Debris stuck in the mower, loose hardware, missing engine mounting bolts and a bad clutch can all contribute to your John Deere shaking.
You must check your mower deck when looking for a vibration. Damaged or unbalanced mower blades, components on your deck, and bad bearings can cause your mower to vibrate.
Detailed information can be found at:
How to Stop Your Lawn Mower from Shaking & Vibration
| Cause | Reason for Problem | Solution |
| Loose or missing engine mounting bolts | Engine bolts are used to reduce the vibration of the mower when the engine is running | Secure engine bolts and replace any missing bolts |
| Clutch is bad | When there is bearing failure and it falls out of the clutch it can cause vibration. A manual engagement clutch can have a bushing and linkages that can fail. | Replace the clutch |
| Unbalanced or damaged mower blades | Damaged and unbalanced blades can send a vibration through your mower. Blades must be balanced before installing | Replace any damaged blades and make sure they are balanced. |
| Material wrapped around the blade spindle | Foreign materials like string or long weeds can get wrapped around your blade shaft causing vibration | Remove all debris and items wrapped around the blade shaft. Check for spindle damage. |
| Bad spindle housing bearings | Vibration can be caused by a bad bearing in the spindle housing. | Replace the bearing in the spindle housing or replace the whole spindle housing assembly |
| Worn pulleys or deck belt | Check deck belt and pulleys for wearing of the belt and bearing failure in the pulleys | Replace any damaged or worn belts and pulleys |
| Debris lodged in mower | The smallest little things can cause your John Deere to excessively vibrate. Check over your mower for debris stuck in the deck or mower. Don’t overlook the small stuff. | Check over your mower deck and mower for any place small items can be stuck in your mower. Remove these foreign materials. |
John Deere Mower Problem 8: Mower Has a Bad or Uneven Cut
Your John Deere mower usually gives you a nice cut each time you mow, however you have noticed your lawn looks bad with an uneven cut. It’s important to start by confirming the tire pressures are correct before you move on to checking and adjusting your mower deck.
Detailed information can be found at:
Reasons Your John Deere Mower Cuts Uneven
| Worn mower blade | Uneven tire pressures | Engine speed is too low |
| Bent mower blade | Unleveled mower deck | Ground speed is too fast |
| Blade installed wrong | Bent blade spindle or spindle bearing | Damaged deck shell |
| Clogged Mower Deck | Worn deck pulleys or belt | Operator error |
John Deere Mower Problem 9: Mower is Leaking Gas
When gas evaporates into the air, it can often be hard to find the place your John Deere mower is leaking gas. There often isn’t a large wet spot to clue you into your problem area. Here is a list of things to check on your mower.
Detailed information can be found at:
Your John Deere Mower is Leaking Gas
| Cause | Reason for Problem | Solution |
| Dirty of Failed Carburetor | The carburetor can collect a buildup of substances remaining from old gas that can cause blockages or parts failures | Clean the carburetor and replace any damaged parts |
| Old Fuel Filter | Filter can become plugged | Replace fuel filter |
| Bad Fuel Pump | Pump can wear and deteriorate over time and may begin leaking at the seams | Replace the fuel pump |
| Bad Fuel Tank | A metal tank can develop a rust hole. A poly tank can leak at the seams of the tank. | Replace the fuel tank. Sometimes, a rust hole can be repaired if you can no longer find a replacement tank. |
| Bad Fuel Shut-Off Valve | Metal and plastic shut-off valves are prone to leaking | Replace the shut-off valve |
| Cracked Fuel Lines | Rubber fuel lines become dry and cracked causing gas to leak | Replace the fuel lines |
| Bad Seal in the Gas Cap | The gas cap seal can fail and no longer seal allowing gas to splash out of the fuel tank around the gas cap | Replace the gas cap |