Common Riding Lawn Mower Problems & Solutions


It doesn’t matter what brand riding mower you bought, when you own it long enough, you will run into problems with it. That is why I put together this guide to help you identify causes for your problem. Follow the links in each section for more in depth information on the problems you are experiencing.

The most common riding lawn mower problems are:

  • Riding mower won’t start
  • Riding mower dies while mowing
  • Riding mower is smoking
  • Riding mower has a weak hydrostatic transmission
  • Riding mower won’t drive straight or steer correctly
  • Riding mower won’t move
  • Riding mower is shaking or vibrating
  • Riding mower is cutting uneven
  • Riding mower is leaking fuel
Common riding lawn mower problems & solutions

This post may include affiliate links. Purchases made through these links may provide a commission for us, at no extra cost to you. As an Amazon Associate we earn from qualifying purchases.

10 Common Riding Lawn Mower Problems & Solutions

Riding Lawn Mower Won’t Start

A riding lawn mower can fail to start when you have a fuel or air restriction due to a plugged air filter, clogging of the fuel system, or failing fuel components. You may also experience bad electrical problems including a dead battery, faulty charging system, dirty spark plug, bad switches, or bad connections that can prevent your riding mower from starting.

Detailed information can be found at:
Reasons Your Riding Mower Won’t Start

CauseReason for ProblemSolution
No gas in the fuel tankFuel tank is emptyFill with fresh fuel
Bad or old fuelFuel breaks down overtime making your fuel less efficient and prone to clogging the fuel systemDrain the fuel tank and fill 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 capThe vent in the cap can get clogged causing your tank to form a vacuum restricting fuel flowUse a thin piece of wire to try to clear the clogged vent. Replace the cap if needed.
Bad spark plugExcessively dirty or broken spark plug; bad connection; not gapped correctlyReplace with a new spark plug, secure connections and ensure it is gapped to manufacturer specifications
Plugged air filterDirt and grass can plug the air filter preventing air flowRemove the filter and clean it. Replace the filter if it is in bad condition.
Plugged fuel filterA dirty fuel filter will restrict fuel flowReplace the fuel filter
Bad fuel pumpA failed or leaking fuel pump will no longer create pressure needed to pump fuelReplace the fuel pump
Blocked fuel linesBad fuel deposits and dirt can build up and clog the fuel lines preventing the engine from getting the required fuelUse a carb cleaner and compressed air to clear the clog out of the fuel line. Replace line if necessary.
Dirty carburetorThe carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flowClean the components making up the carburetor. Replace if needed.
Bad battery or loose & dirty terminalsA dead battery, loose cables or corroded terminals can cause starting problemsCharge your battery and replace if it won’t hold a charge. Make sure your cables are tight and clean the corrosion from terminals.
Bad safety switchSafety switches is a safety measure that exist 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 coilYour mower will not start when either the ignition switch or coil is badTest and replace a bad switch
Broken recoilA pull start mower may have a damaged or broke recoil preventing the recoil to initiate starting your engineCheck recoil to see if it can be restrung or broke parts, like the pulley, can be replaced. Replace the recoil assembly if needed.
Bad charging systemA charging system that can’t keep your mower charged and is constantly draining the battery must be repaired to prevent starting problems.Take your lawn mower to your local riding mower dealership for assistance identifying which part of the charging system has failed.
Reasons Your Riding Lawn Mower Won’t Start

Riding Lawn Mower Starts Then Dies

You’re mowing the lawn when your riding mower suddenly dies. Being stuck in the middle of your yard with a mower that is dead is frustrating. A riding mower may die when old fuel is used causing clogging in the fuel components or engine damage.

Your engine needs to be kept cool to prevent damage or it will die. A plugged air filter, wrong engine oil, incorrect oil level and plugged mower deck can contribute to your engine overheating and shutting down.

A riding mower can also die after its been running from a faulty charging system that isn’t able to keep your battery charged, a dirty spark plug, bad ignition coil.

Detailed information can be found at:
Your Riding Lawn Mower Starts Then Dies

CauseReason for ProblemSolution
Bad fuelFuel breaks down overtime making your fuel less efficient and prone to clogging the fuel system and engine damageDrain the fuel tank and fill with fresh fuel. Use a fuel additive like Sea Foam to stabilize the fuel and assist with cleaning the fuel system
Plugged air filterDirt and grass can plug the air filter preventing air flowRemove the filter and clean it. Replace the filter if it is in bad condition.
Dirty or broken cooling finsCooling fins get packed with dirt, oil and grass not allowing air to effectively cool the engine blockReplace broken fins and clean the cooling fins.
Clogged fuel lines or filterBad fuel deposits and dirt can build up and clog the fuel lines preventing the engine from getting the required fuelUse a carb cleaner and compressed air to clear the clog out of the fuel line. Replace a plugged fuel filter.
Dirty carburetorThe carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flowClean all components making up the carburetor. Replace if needed.
Too Much Engine OilToo much engine oil increases pressure in the crankcase causing it to overheat and dieCorrect your engine oil level by removing a little oil
Bad Spark PlugDirty or damaged spark plug causes 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 CoilA windings on the coil can separate and short out on a bad ignition coilCheck for a break in the continuity using an ohm meter and replace is found bad
Choke is in the Wrong PositionA 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 ChargingA battery that doesn’t hold a charge or a bad charging system that can’t keep the battery charged will cause your riding mower 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.
Bad Gas CapGas 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 DeckClogged mower deck causes a strain on the engine causing it to work hard and possibly shut downPeriodically scrape your mower deck to keep it clean
Reasons Why Your Riding Lawn Mower Dies While Mowing

Riding Lawn Mower is Smoking 

Smoke rolling out of your mower can be very alarming. This can sometimes be fixed by replacing your air filter, correcting your engine oil level or replacing a gasket causing an oil leak . Other times, it is not so simple of a fix. The engine may have an internal problem that will need to have tests performed by a small engine mechanic to narrow down the problem.

Detailed information can be found at:
This is Why Your Riding Mower is Smoking

CauseReason for ProblemSolution
Plugged air filterDirt and grass can plug the air filter preventing air flowRemove the filter and clean it. Replace the filter if it is in bad condition.
Too much oil in the crankcaseExcessive oil can cause pressure to build in the engine allowing oil to get into the cylinder through the valve trainDrain a little engine oil until it is at the manufacturers recommended oil level.
Engine oil level is too lowLack 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 have this fix your engine problem.
Internal problems including the piston ring, valve train or engine gasketInternal engine problems can have a detrimental effect on your mower if they are not caught soon enough and fixed.Have your mower diagnosed by your local small engine repair shop.
Reasons Why Your Riding Lawn Mower is Smoking

Riding Lawn Mower Hydrostatic Transmission is Weak

CauseReason for ProblemSolution
Bad drive beltA bad drive belt can cause your pump not to work efficientlyReplace a frayed, cracked or worn belt
Bad tensioner pulleyWhen a tensioner pulley fails, it fails to keep tension on the drive beltReplace the pulley and grease the tensioner arm
Low or old hydraulic oilLow or old hydraulic oil can fail to lubricate the hydraulic system causing your hydraulic system to seem weakChange your hydraulic oil at regularly intervals as recommended by riding mower manufacturer.
Check your hydraulic oil periodically to ensure your hydraulic fluid is full.
(Some transmissions systems are sealed and they can’t be serviced. If you are having troubles with a sealed system, see your dealer).
Reasons Why Your Riding Lawn Mower’s Hydrostatic Transmission Seems Weak

Riding Lawn Mower Won’t Drive Straight or Steer Correctly

It can get frustrating when you are always having to adjust the operating of your mower because it is pulling to the right or left. Here is a list of items to check on a riding lawn mower to make the necessary corrections to get your mower to drive straight.

CauseReason for ProblemSolution
Incorrect tire pressureUnequal tire pressure can cause your mower to pull to one side.Check tire pressures and keep them filled to the manufacturers spec. Tires on each side of your mower requires equal pressures.
Worn or loose steering components in riding mowerWorn bushings, washers and gears can cause your mower to not steer one way or the otherInspect and replace the parts that failed on your steering system
Reasons Why Your Riding Mower Won’t Drive Straight or Steer Correctly

Riding Lawn Mower Won’t Move

A riding lawn mower may not move when the drive levers on hydrostatic mowers are not in the correct operating position. A bad tensioner, missing idler arms spring and worn belt can also affect a riding mower’s movement. Running old hydraulic fluid or having air in the system can cause your mower to move slowly or not at all.

Detailed information can be found at:
9 Reasons Your Mower Won’t Move or Go Forward

CauseReason for ProblemSolution
Drive release lever in the wrong positionThe drive release lever allows hydrostatic mowers to roll freelyThe drive release lever must be in the operating position.
Missing key in the axleYour riding mower may have a small key in the axle that may have fallen out of placeReplace the key in the axle
Bad tensioner pulleyThe bearing in the tensioner pulley can failReplace the tensioner pulley
Missing idler arm springIf the idler arm spring breaks or goes missing, it can no longer place tension on the drive beltReplace the broken or missing spring
Worn drive beltA worn drive belt will slip on the pulley and cause your mower to run sluggish. The belt can break or fall of the pulley and your mower will no longer move.Replace a worn drive belt
Low or old hydraulic oilLow or old hydraulic oil can fail to lubricate the hydraulic system causing your hydraulic system to seem weakChange your hydraulic oil at regularly intervals as recommended by your riding mower manufacturer.
Check your hydraulic oil periodically to ensure your hydraulic fluid is full.
(Some transmissions systems are sealed and they can’t be serviced. If you are having troubles with a sealed system, see your dealer).
Hot hydraulic fluidHot hydraulic fluid can be a sign of damage to your hydrostatic transmission systemLet your hydraulic oil cool. If you find your mower runs fine when it is cold, but does becomes weak when the hydraulic system gets hot, have your mower checked at your local manufacturer dealership.
Air in the hydraulic systemAir must be bled from the hydraulic system after changing your hydraulic fluid or the mower will not be able to move at normal speedsFollow your mower manufacturer’s procedures for changing hydraulic fluid and bleeding air from the system in your owner’s manual.
Reasons Why Your Riding Lawn Mower Will Not Move or Go Forward

Riding Lawn Mower is Vibrating

When your lawn mower begins vibrating and shaking more than normal, it’s time to look over your mower carefully for any extra debris caught in your mower. You would be surprised at some of the little things I have found stuck in a mower that cause a significant vibration.

A riding mower 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 Riding Lawn Mower Vibration

CauseReason for ProblemSolution
Loose or missing engine mounting boltsEngine bolts are used to reduce vibration of the mower when the engine is runningSecure engine bolts and replace any missing bolts
Clutch is badWhen 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 bladesDamaged and unbalanced blades can send a vibration through your mower. Blades must be balanced before installingReplace any damaged blades and make sure they are balanced.
Material wrapped around the blade spindleForeign materials like string or long weeds can get wrapped around your blade shaft causing vibrationRemove all debris and items wrapped around the blade shaft. Check for spindle damage.
Bad spindle housing bearingsVibration can be caused by a bad bearing in the spindle housing.Replace bearing in the spindle housing or replace the whole spindle housing assembly
Worn pulleys or deck beltCheck deck belt and pulleys for wearing of the belt and bearing failure in the pulleysReplace any damaged or worn belts and pulleys
Debris lodged in mowerThe smallest little things can cause a riding mower 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.
Reasons Your Riding Lawn Mower is Vibrating

Riding Lawn Mower Has a Bad or Uneven Cut

Detailed information can be found at:
Reasons Your Riding Mower is Cutting Uneven

Worn mower bladeUneven tire pressuresEngine speed is too low
Bent mower bladeUnleveled mower deckGround speed is too fast
Blade installed wrongBent blade spindle or spindle bearingDamaged deck shell
Clogged Mower DeckWorn deck pulleys or beltOperator error
Reasons Your Riding Lawn Mower is Cutting Uneven

Riding Lawn Mower is Leaking Gas

Fuel will evaporate making it increasingly difficult to find a lawn mower fuel leak on your mower if you don’t physically see it dripping or form a wet spot. A riding mower 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 Riding Mower is Leaking Gas

CauseReason for ProblemSolution
Dirty of Failed CarburetorThe carburetor can collect a buildup of substances remaining from old gas that can cause blockages or parts failuresClean the carburetor and replace any damaged parts
Old Fuel FilterFilter can become pluggedReplace fuel filter
Bad Fuel PumpPump can wear and deteriorate over time and may begin leaking at the seamsReplace the fuel pump
Bad Fuel TankA 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 ValveMetal and plastic shut-off valves are prone to leakingReplace the shut-off valve
Cracked Fuel LinesRubber fuel lines become dry and cracked causing gas to leakReplace the fuel lines
Bad Seal in the Gas CapThe gas cap seal can fail and no longer seal allowing gas to splash out of the fuel tank around the gas capReplace the gas cap
Places Your Riding Lawn Mower May Be Leaking Gas

Additional Guides for Your Riding Lawn Mower

Check out these articles for additional help with your riding mower:

How to Service Your Riding Mower: Step-By-Step

Your Riding Mower Isn’t Getting Fuel

Powered Equipment Team

We're just a guy and a girl obsessed with outdoor power equipment! We are excited to share the knowledge and tips we have learned over our combined 55 years in the power equipment industry. We have both ran equipment dealerships and took pleasure in helping our customers everyday providing equipment repair, parts, purchasing, and business tips to our residential and commercial clients. We hope our blog will help you with your next purchase, repair, or project.

Recent Posts