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Common Push Mower Problems & Solutions

Owning a push mower doesn’t come without its problems. If you own a push mower long enough, you’re bound to run into an issue like your mower won’t start, it shuts off while mowing or it begins shaking.

While many of these problems can be avoided or caught early by performing routine maintenance on your push mower, you will probably end up running into some type of problem you’ll need to repair. I put together this guide to help give you a reference to help you identify the cause of your problem.

The most common push mower problems are:

  • Push mower won’t start
  • Push mower dies while mowing
  • Push mower is smoking
  • Push mower is shaking or vibrating
  • Push mower is cutting uneven
  • Push mower is leaking gas
Common push mower problems and solutions

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Follow all safety instructions provided in your equipment operators manual prior to diagnosing, repairing or operating. Consult a professional if you don’t have the skills, knowledge or are not in the condition to perform the repair safely.

Common Push Mower Problems & Solutions

Push Mower Won’t Start

A push mower that won’t start once you pull it out of storage for the mowing season is often the result of old fuel sitting in the mower over winter. Old fuel can clog and damage fuel components.

Other reasons a push mower won’t start are a bad fuel cap, failed mechanical components, plugged filters, loose wires, failed electrical components or a broken recoil.

Detailed information can be found at:
Solved! Your Push 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 flowTry to clean the cap and remove 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
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.
Reasons a Push Mower Won’t Start

Push Mower Dies While Mowing

A push mower will start and then die when it experiences an air or fuel restriction caused by bad fuel; a plugged air or fuel filter; clogged fuel lines; or dirty carburetor.

The ignition coil can also be the cause when it gets hot and the windings separate.

Detailed information can be found at:
Why Your Push Mower Dies While Mowing (Solved!)

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.
Clogged fuel linesBad 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
Dirty carburetorThe carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flowClean all the components making up the carburetor. Replace if needed.
Bad Ignition CoilThe windings on the ignition coil can separate and short out when the mower is hotTest the coil for a break in the continuity. Replace the ignition coil.
Reasons Why a Push Mower Dies While Mowing

Push Mower is Smoking

A push mower can start to smoke when the engine gets hot because of a lack of air flow or low engine oil in the crankcase. Valve train and piston ring problems in the engine can cause the mower to smoke from pushing oil in to the cylinder to burn off.

You will also need to check for engine oil leaks where oil drips onto the muffler when looking for a smoking issue.

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

CauseReason for ProblemSolution
Plugged air filterDirt and grass can plug the air filter preventing air flow causing the engine to become hot. It can also result in smoking from burning more fuel than the air required to form a combustion.Remove 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.
Tipped push mowerTipping your mower or using it on a hillside can cause oil to get onto the air filter or carburetor.Always tip your mower with the carburetor and filter located on the high side of the push mower. Clean the carburetor and replace an oil covered filter.
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.Bring your push mower to your local small engine repair shop for troubleshooting
Reasons Why a Push Mower is Smoking

Push Mower is Vibrating

A push mower can begin vibrating so much it feels like your holding on to a jack hammer. This vibration can come from debris stuck in your mower, worn engagement linkages, bad clutch or loose engine mounting bolts.

Bad deck components can also cause your push mower to shake. This can from unbalanced mower blades or damaged crankshaft.

Detailed information can be found at:
Your Push Mower is Vibrating

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
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.
Bent crankshaftWhen the blades are not the cause of your problem, check the crankshaft. A crankshaft can become bent when your blades hit a solid object.Have a lawn mower small engine mechanic replace a bent crankshaft. The engine will have to be removed to do this.
Loose linkages and bushingsLinkages and bushings can wear and become loose causing a vibration.Tighten linkages and replace any worn parts.
Debris lodged in mowerThe smallest little things can cause your push 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 a Push Mower is Vibrating

Push Mower Has a Bad or Uneven Cut

The first thing to look at when trying to find your bad cut is the wheel. When the wheel is damaged, the deck will not sit level and will give you an uneven cut.

Next, address the mower deck items that can impact the cut including a bent or worn mower blade, an incorrectly installed blade, a bent crankshaft and a clogged mower deck.

Detailed information can be found at:
Reasons a Push Mower Cuts Uneven

Worn mower bladeDamaged wheelEngine speed is too low
Bent mower bladeIncorrect cutting height adjustmentGround speed is too fast
Blade installed wrongBent crankshaftClogged mower deck
Reasons a Push Mower is Cutting Uneven

Push Lawn Mower is Leaking Gas

You smell the odor of fuel in the air, but you can’t find where your push mower is leaking gas. This could be because fuel will evaporate leaving no signs of a leak after the mower has been sitting a while.

Unless you have a large leak with a fuel puddle on the floor, you will need to check each fuel component in your mower for leaks.

A fuel leak must be fixed. Running a mower that continually leaks can damage the lawn in addition to the added cost of fuel.

Detailed information can be found at:
Your Push 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 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
Cracked Primer BulbThe rubber of the primer bulb can begin leaking when it cracks or isn’t attached well to the fuel hose.Replace the primer bulb
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 a Push Mower May Be Leaking Gas