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, shut off while mowing, or 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
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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.
Table of Contents
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
| 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 | Try to clean the cap and remove 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 |
| 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. |
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 a 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!)
| 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. |
| Clogged 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 |
| Dirty carburetor | The carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flow | Clean all the components making up the carburetor. Replace if needed. |
| Bad Ignition Coil | The windings on the ignition coil can separate and short out when the mower is hot | Test the coil for a break in the continuity. Replace the ignition coil. |
Push Mower is Smoking
A push mower can start to smoke when the engine gets hot because of a lack of airflow 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 into 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
| Cause | Reason for Problem | Solution |
| Plugged air filter | Dirt and grass can plug the air filter preventing air flow and causing the engine to become hot. It can also result in smoking from burning more fuel than the air required to form combustion. | 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. |
| Tipped push mower | Tipping 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 gasket | Internal 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 |
Push Mower is Vibrating
A push mower can begin vibrating so much it feels like you holding on to a jackhammer. 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
| 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 |
| 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. |
| Bent crankshaft | When 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. Note: it may be less expensive to purchase a new mower. |
| Loose linkages and bushings | Linkages and bushings can wear and become loose causing a vibration. | Tighten linkages and replace any worn parts. |
| Debris lodged in mower | The 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. |
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 blade | Damaged wheel | Engine speed is too low |
| Bent mower blade | Incorrect cutting height adjustment | Ground speed is too fast |
| Blade installed wrong | Bent crankshaft | Clogged mower deck |
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
| 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 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 |
| Cracked Primer Bulb | The 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 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 |
