When you own any mechanical piece of equipment long enough, it’s bound to start giving you trouble. The same is true of your lawn tractor. It doesn’t matter what brand or model you purchase. They are all going to fail at some point.
A lawn tractor can experience problems when it won’t start or dies after it has been mowing for a while. Other common problems that develop in a lawn tractor are smoking, vibration, cutting, and hydraulic problems.
I put together a guide to these common problems and solutions. You will find additional links providing more detailed information when you experience an issue with your lawn tractor.
Before performing any work on your tractor, follow all safety guidelines outlined in your owner’s manual.
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Follow all safety instructions provided in your equipment operator’s manual before 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.
9 Common Lawn Tractor Problems & Solutions
Won’t Start
Lawn tractors require fuel, air, and spark to start. When it isn’t receiving one of these items, it will fail to start. A lawn tractor won’t start when old fuel clogs the fuel system; the air filter is plugged; the fuel cap is bad; the fuel pump is faulty; the battery is bad; the switch is faulty, or the carburetor is dirty.
Detailed information can be found at:
Reasons Your Lawn Tractor Won’t Start
| Cause | Reason for Problem | Solution |
| No fuel 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 | Try to clean the cap to remove the clog. Replace with a new cap if needed. |
| Bad spark plug | Excessively dirty or broken spark plug; bad connection; or not correctly gapped | 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 lawn tractor from starting in certain situations. When a switch fails, your tractor may not start. | Test and replace faulty safety switch |
| Bad ignition switch or coil | Your lawn tractor will not start when either the ignition switch or coil is bad | Test and replace a bad switch or coil |
Starts Then Dies
Many of the items that prevent a lawn tractor from starting can also be the cause of it dying while you’re using it. Along with items such as old fuel, bad spark plug, and clogged fuel lines, a lawn tractor can die when it overheats.
This can be due to a plugged air filer, buildup around the cooling fins, insufficient oil level, or a plugged mower deck.
A lawn tractor can shut down after it has been running when a faulty ignition coil becomes hot and shorts out; the charging system is not working, or the fuel cap vent is plugged.
Detailed information can be found at:
Your Lawn Tractor 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 carburetor 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 | A 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 | Windings on the coil can separate and short out on a bad ignition coil | Check for a break in the continuity using an ohmmeter 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 |
| Battery is Not Charging | A battery that doesn’t hold a charge or a bad charging system that can’t keep the battery charged will cause your lawn tractor to die after running. | Test your battery and charging system. Replace any electrical components found to be bad. Read more about testing your battery and charging system here. |
| Fuel Gas Cap | Gas caps have vents for air to pass through. When the vents get clogged, the fuel tank will cause fuel restrictions. | Replace a fuel cap that no longer vents |
| Clogged Mower Deck | 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 |
Smoking
There are many reasons a lawn tractor can start to smoke. While some causes can be fixed if caught early, having internal engine damage will be a more in-depth costly repair.
A lawn tractor can begin smoking when a filter is plugged with dirt and debris restricting airflow to the engine. It can also smoke when the engine oil level is too high or too low. Piston ring, valve train, and gasket problems can also result in smoke emitting from your tractor.
Detailed information can be found at:
This is Why Your Lawn Tractor 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 lawn tractor if they are not caught soon enough and fixed. | Have your lawn tractor diagnosed by your local small engine mechanic. |
Hydrostatic Transmission is Weak
| 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 your lawn tractor manufacturer. 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). |
Won’t Drive Straight or Steer Correctly
It can get frustrating when you are always having to compensate for your lawn tractor pulling to the right or left. Here is a list of items to check on a lawn tractor to make the necessary corrections to get your tractor to drive straight.
| Cause | Reason for Problem | Solution |
| Incorrect tire pressure | Unequal tire pressure can cause your lawn tractor to pull to one side. | Check tire pressures and keep them filled to the manufacturer’s spec. Tires on each side of your lawn tractor require equal pressure. |
| Worn or loose steering components on your lawn tractor | Worn bushings, washers, and gears can cause your lawn tractor to not steer one way or the other | Inspect and replace the parts that failed on your steering system |
Won’t Move
A lawn tractor may not move when the drive levers on a hydrostatic lawn tractor are not in the correct operating position.
A bad tensioner, missing idler arms spring, and worn belt can also affect its movement. Running old hydraulic fluid or having air in the system can cause your lawn tractor to move slowly or not at all.
Detailed information can be found at:
9 Reasons Your Mower Won’t Move or Go Forward
| Cause | Reason for Problem | Solution |
| Drive release lever in the wrong position | The drive release lever allows hydrostatic lawn tractors to roll freely | The drive release lever must be in the operating position. |
| Missing key in the axle | Your lawn tractor may have a small key in the axle that may have fallen out of place | Replace the key in the axle |
| 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 |
| Worn drive belt | A worn drive belt will slip on the pulley and cause your lawn tractor to run sluggishly. The belt can break or fall off the pulley and your tractor will no longer move. | Replace a worn drive belt |
| 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 your lawn tractor manufacturer. 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 lawn tractor runs fine when it is cold, but becomes weak when the hydraulic system gets hot, have your tractor checked at your local manufacturer dealership. |
| Air in the hydraulic system | Air must be bled from the hydraulic system after changing your hydraulic fluid or the lawn tractor will not be able to move at normal speeds | Follow your lawn tractor manufacturer’s procedures for changing the hydraulic fluid and bleeding air from the system in your owner’s manual. |
Vibration
When your lawn tractor begins vibrating and shaking more than usual, it’s time to look over your lawn tractor carefully for any extra debris caught in your tractor.
You would be surprised at some of the little things I have found stuck in a lawn tractor that cause a significant vibration.
A lawn tractor vibration can be caused by running unbalanced or damaged mower blades; loose and missing hardware; bearing failure in the pulleys and spindle housings; and a bad clutch.
Detailed information can be found at:
Solved! Your Lawn Tractor is Vibrating
| Cause | Reason for Problem | Solution |
| Loose or missing engine mounting bolts | Engine bolts are used to reduce the vibration of the lawn tractor 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 lawn tractor. 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 the lawn tractor | The smallest little things can cause a lawn tractor to excessively vibrate. Check over your tractor for debris stuck in the deck or tractor. Don’t overlook the small stuff. | Check over your mower deck and lawn tractor for any place small items can be stuck in your tractor. Remove these foreign materials. |
Bad or Uneven Cut
Detailed information can be found at:
Reasons Your Lawn Tractor 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 |
Leaking Gas
Fuel will evaporate making it increasingly difficult to find a fuel leak on your lawn tractor. A tractor can begin leaking gas from old, dry, or degraded fuel components including the fuel filter, carburetor, fuel pump, and fuel lines. It can also be from a failing seal in a fuel cap.
Detailed information can be found at:
Why Your Lawn Tractor 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 |