Lawn Mower Troubleshooting Tips

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Ready for some mowing sessions but your lawn mower is faulty, then there are a few things to do.

Continue reading until the end to learn about some troubleshooting tips that can solve the problem so that you can have a hassle-free mowing experience.

Ready? Let’s dive right into it:

Contents show

1.  Troubleshooting Lawn Mower Starting Problems

If your lawn mower won’t start, the likely causes are old gas, faulty spark plug, blocked fuel filter, bad battery and clogged air filter. 

Here are some troubleshooting tips to solve lawn mower starting problems:

Clean or Replace Spark Plug

Faulty spark plugs are one of the common reasons why your mowing machine won’t start. The spark plug can be disconnected, worn, dirty or loose.

Before getting them replaced, you can clean and tighten the old spark plugs if they can still work.

Replace them if they do not work after cleaning. Spark plugs are located at the side or back of your mower engine.

Drain Old Gas

It is important to check your gas tank if you have left the mower outside. In this case, the mower may have been contaminated by rain. 

To inspect your fuel tank, you need follow these tips:

  • Check the fuel level.
  • It is best to inspect if there is water floating in the gas.
  • If you aren’t sure about the presence of water in the fuel tank, drain a little bit of gas and inspect if there is water.
  • Drain the old gas completely and use compressed air to dry the tank. Refill the fuel tank with new gas.

Note: Ensure that you detach the spark plugs so that your mowing machine won’t accidentally start while checking it.

Replace Bad Fuel Filter

If you discover that your gas isn’t getting to the engine’s combustion chamber during the ignition process, it may cause your mower not to start.

To check the fuel filter, you need to tap the side of the carburetor to push your gas along. 

You can also swap it out if that technique does not work. It is best to replace it if it is bad.

Test and Replace Bad Battery

Several electric ride-on mowers make use of batteries. Similar to the car battery, the mower’s battery can deteriorate over time which may cause it to struggle or not hold a charge.

You can replace it if it is bad. Here are some tips on how to check your battery:

  • Check the headlights. If they are dim, it means that your battery is bad.
  • Check your battery for corrosion, cracks or other issues.
  • Use a multimeter to test the battery charge.
  • Replace the battery if it is bad

Clean or Replace the Air Filter

Ensure that you always inspect your air filter while troubleshooting a mower that does not start. Check the owner’s manual to locate where the air filter is.

If it looks dirty, make sure that you take it off and clean the buildup. If it doesn’t work, you may need to replace it.

Check the Oil Level And If It is Not Contaminated With Water

It is advisable to check if there is adequate oil in your mower. The oil may be contaminated with water. If the oil has turned white or milky, it means that water has contaminated it.

2. Lawn Mower with Uneven Cuts: 2 Troubleshooting Tips

Uneven mowing is often caused by dull blades and unbalanced grass build-up. Here are some troubleshooting tips to solve uneven cuts:

Sharpen the Mower Blades

It is advisable to sharpen your blades so that your mower can function well.

You can sharpen the mower blades by using a metallic file or you take the mower to a local mower repair shop for sharpening. If they are worn, it is best to replace them.

Clean Grass or Debris Build-Up

Ensure that you clean the buildup of leaves, grass and other debris to enable your mower to cut evenly. You should also empty the grass or debris buildup.

3. Starter Rope That is Either Stuck or Too Hard to Pull

If your starter rope is stuck or too hard to pull, it may be as a result of  engaged flywheel brake or clogged blades. You can check these fixes to solve the issue:

Disengage the Flywheel Brake

The simple thing to do is to ensure that you completely disengage the flywheel brake before you pull the starter rope. Make sure that you do not press it against the handle of the mower.

Check and Clean the Blades

You may need to inspect the blades. They might get clogged by grass or may be touching the ground. To check and clean the blades, you need to:

  • Lay your lawn mower down on a flat surface.
  • Disengage the spark plug
  • Get rid of dirt or grass cuttings on the blades and try again.

4. Troubleshooting Lawn Mower Smoking Issues

To troubleshoot smoking issues, you need to look out for an overfilled or leaking oil chamber. Here are some tips to follow:

  • Turn off the engine and wait for it to cool down before inspecting the chamber for leaks.
  • Ensure that the cap is sealed tightly before you restart your mowing machine.
  • In some cases, you may need to seek the help of an expert to solve the problem.

5. Lawn Mower Won’t Stay Running

This problem can arise as a result of old/dirty fuel, a clogged carburetor or a dirty air filter.

Here are some of the troubleshooting tips to solve the issue of your mower that won’t stay running.

Replace Spark Plug

It is important to check if the spark plug is defective. Replace it if  you discover that it is faulty. To change the spark plug, you should do the following steps:

  • Get the required tools for the replacement
  • Locate where the spark plug is positioned.
  • Disconnect the wire of the spark plug.
  • Take off the spark plug.
  • Install a new spark plug.
  • Reconnect the cable and start the engine to confirm if your mowing machine is working well.

Replace Dirty, Old or Undiluted Gas

Old gas can leave a sticky residue in your motor and cause the carburetor and fuel filter to get clogged. To replace the old, undiluted and dirty fuel with a fresh one.

Clean or Replace Clogged Carburetor

If you notice that your carburetor is clogged or bad, you need to clean or replace it. The tools needed to clean the carburetor include a stiff wire, a pair of plastic gloves and a carburetor.

The tools needed to replace a carburetor also include clamps, an adjustable wrench, a nut driver, needle nose pliers, a socket/ratchet set, an organic vapor respirator and four in one screwdriver.

To clean the carburetor, you need to follow these tips:

  • The first thing to do is to check the air filter to be sure it is free of debris.
  • Inspect the connections between that run from the carburetor’s choke plates and throttle.
  • Use a carburetor cleaner to remove deposits from the mower’s carburetor.
  • Check your carburetor’s settings to determine if there is anything that needs to be adjusted.

Note: It is advisable to replace the carburetor if it is bad.

4. Clean or Replace Plugged Air Filter

You need to check and clean the air filter regularly to enable your mower to stay running. Here are some tips on how to clean your paper or foam air filter.

Paper Air Filter

  • Take off the air filter from the mower’s housing.
  • Clean any dirt that is in the housing. Make sure that the dirt does not enter the air intake.
  • Tap the filter against a solid surface.
  • Hold the air filter to a light source and ensure that you can observe a light that shines through the paper element. If you can’t see light shine through it, it means that you should get a new one.
  • You can now re-install the air filter and attach the air filter’s housing cover

Foam Air Filter

  • Take off the air filter from the mower’s housing.
  • Clean any dirt that is in the housing. Make sure that the dirt does not fall into the air intake.
  • Check the filter for dark spots or if it is brittle, torn or dry. Replace the filter if you notice these signs.
  • Use water and mild dish soap to wash the foam filter. Rinse to take off the soap from the foam filter.
  • Lay it flat to dry. You can also sun dry it to fasten its drying process.
  • Coat your air filter with a foam air filter oil once it is totally dry.
  • Reinstall the air filter and attach the air filter’s housing cover.

6. Lawn Mower Loses Power: 5 Troubleshooting Tips

If your mowing machine loses power, the most likely causes are plugged air filter, dirty spark plug, low engine oil level, too much load on the engine and dirty cooling fins

Here are some troubleshooting tips that can aid your to solve the issues:

Clean or Replace the Air Filter

You may need to clean or replace the air filter to prevent your mowing machine from losing power. Follow the following tips to clean your paper or foam air filter:

Paper Air Filter

  • Take off the air filter from the mower’s housing.
  • Clean any dirt that is in the housing. Make sure that the dirt does not enter the air intake.
  • Tap the filter against a solid surface.
  • Hold the air filter to a light source and ensure that you can observe a light that shines through the paper element. If you can’t see light shine through it, it means that you should get a new one.
  • You can now re-install the air filter and attach the air filter’s housing cover

Foam Air Filter

  • Take off the air filter from the mower’s housing.
  • Clean any dirt that is in the housing. Make sure that the dirt does not fall into the air intake.
  • Check the filter for dark spots or if it is brittle, torn or dry. Replace the filter if you notice these signs.
  • Use water and mild dish soap to wash the foam filter. Rinse to take off the soap from the foam filter.
  • Lay it flat to dry. You can also sun dry it to fasten its drying process.
  • Coat your filter with a foam air filter oil once it is totally dry.
  • Reinstall the air filter and attach the air filter’s housing cover.

Replace Bad Spark Plug

Make sure that you check the spark plug for signs of oil, carbon and dirt buildup on its tip. It is better to replace it if it is bad. 

Alternatively, you can use a wire brush to clean the spark plug if it is only dirty and it is not dark in color.

Check the Engine Oil

It is important to always check the engine oil in your mowing machine before using it. This will prevent significant damage to your mower.

Avoid Too Much Load On Your Engine

You can prevent your lawn mower from losing power by avoiding too much load on the engine.

To do this, you need to slow down your mower’s speed, get rid of grass buildup on the deck, sharpen the mower blades and avoid mowing wet and extremely tall grass.

If you need to cut very tall grass, you can perform regular cuttings. 

If it gets a bit long, adjust the deck on the highest position to do the first cutting and lower it for the next cutting.

Clean or Replace Cooling Fins

You can just get rid of any build-up on the cooling fins if it is in good condition. You may need to replace them if they are in bad condition.

7. Lawn Mower Won’t Start Just Clicks

Your lawn mower clicks but won’t start when the solenoid is defective; the battery cables and terminals are corroded or loose; the starter motor is faulty or the battery is weak. 

You can follow the following troubleshooting tips to solve the problem:

Test and Replace Bad Starter Solenoid

Your solenoid may be bad if you hear a hum or click when you turn on the ignition key. You will need a continuity light, volt-ohms meter, some wrenches and a screwdriver to test the solenoid.

It is advisable to replace the solenoid if you can start your mowing machine by bypassing it.

Remove Corrosions Found on Cables and Replace Them if they Are Loose or Broken

It is best to remove corrosion on wires and terminals. To remove corrosion on terminals, you need to disconnect the mower battery and clean these terminals.

Use a wire brush, two cups of water and a baking soda mix that consists of three heaping tablespoons. You can also replace any bad terminal.

Charge Weak Battery or Replace Bad Battery

You can simply use a battery charger to charge a weak battery or replace it if it does not hold a charge.

Replace Bad Starter Motor

If you have checked the solenoid, battery, cables and terminals and they are in good condition, your starter may be the issue.

Replace the starter motor if it is bad. You can also contact a professional that specializes in starter repairs to help you fix it.

8. Troubleshooting a Lawn Mower That Runs Rough

Your lawn mower may run rough due to a bad spark plug, plugged air filter, bad fuel filter and old gap. To troubleshoot this problem, you have to follow these tips:

Replace Bad Spark Plug

It is advisable to replace the spark plug when the electrode is burnt, the porcelain is cracked or when the tip is very dark in color.

Ensure that the spark plug wire is securely attached and the spark plug gap is correct. If you want to clean the spark plug, you can use a wire brush to clean the build-up

Clean or Replace Plugged Air Filter

It is also important to clean the air filter or replace it if it is in bad condition. Here are some tips on how to clean your paper or foam air filter.

Paper Air Filter

  • Take off the air filter cover from its filter housing.
  • Remove the air filter and ensure that dirt does not enter the air intake
  • Clean any dirt that is in the housing. Make sure that the dirt does not enter the air intake.
  • Tap the filter against a solid surface.
  • Hold the air filter to a light source and ensure that you can observe a light that shines through the paper element. If you can’t see light shine through it, it means that you should get a new one.
  • You can now re-install the air filter into the housing.
  •  Re-attach the air filter cover

Foam air filter

  • Take off the air filter from the mower’s housing.
  • Clean any dirt that is in the housing. Make sure that the dirt does not fall into the air intake.
  • Check the filter for tears, dark spots or if it is brittle or dry. Replace the filter if you notice these signs.
  • Use water and mild dish soap to wash the foam filter. Rinse to take off the soap from the foam filter.
  • Lay it flat to dry. You can also sun dry it to fasten its drying process.
  • Coat your filter with a foam air filter oil once it is totally dry.
  • Reinstall the air filter and attach the air filter’s housing cover.

Note: You may need to replace it if the foam filter has dark spots or is excessively dirty.

Drain Fuel Tank

Use a siphon fuel tank to drain the gas tank and refill it with a gas that is ideal for your engine type.

Replace Fuel Filter

If you notice that fuel does not flow through the fuel filter, you should replace it. 

The arrow on the filter should face the direction of the fuel flow. In addition, this arrow should also be pointed towards the carburetor and away from the fuel tank.

9. Troubleshooting a Lawn Mower That Fails To Cut Grass

If you notice that your mowing machine does not mow grass, it may be that the grass is wet or too long. Here are some troubleshooting tips to follow:

Avoid Mowing On Wet Grass

You need to avoid mowing wet grass. Mowing during wet conditions can clog your mowing machine.

Adjust the Deck’s Height and Mow at a Slower Pace

If you notice that the grass is too long for the mower’s setting, you might need to raise the deck height above its standard settings before you start mowing your overgrown grass. 

It is also advisable to mow at a slower pace while mowing very tall grass.

10. Lawn Mower Overheating

Your lawn mower may overheat as a result of blocked cooling fins, blocked air filter, low engine oil and a mower deck full of debris. 

You need to follow these troubleshooting tips to solve the overheating:

Clean Cooling Fins

You need to take off the engine covers and clean the cooling fins. If you don’t want to handle it yourself, you can also take it to a local lawn mower repair shop for regular maintenance.

Replace Blocked Filters

If you notice that the engine gets hot due to inadequate air, you may need to inspect and replace it if it is bad.

Check Engine Oil Before Use

To keep your engine running at an optimal level, always perform the engine oil changes. You should also check the level of the engine oil before you make use of your mowing machine. 

You can add if the oil level is lower than the recommendations of the manufacturer.

Clean Mower Deck Full of Debris

To prevent the engine from overheating, it is important to clean the deck regularly and also check it for damage

11. Troubleshooting a Lawn Mower That Loses Speed

When your mowing machine slows down, the problem may come from a defective drive belt or dysfunctional battery. The drive belt is located in the motor’s casing. Here are

Reattach or Replace Drive Belt

Inspect your drive belt when the mower is turned off. You can reattach it if it is just loose and not damaged. If it is faulty, it is advisable to replace it.

Check the Battery

In some cases, some lawn mower batteries may cause this problem. It is advisable to seek the help of a professional to solve the problem.

Tips to Follow Before Troubleshooting Your Lawn Mower 

  • Always refer to the operator’s manual before attempting troubleshooting tips on your mower.
  • Disconnect the spark plug before removing the grass buildup that is underneath the deck.
  • Take off all sources of flammable material such as stoves, cigarettes and naked flames and other flammable objects when working on the tank or fuel lines.
  • Ensure that you drain the mower’s tank if you estimate that the fuel level will reach the cap.