Lawn Mower Makes Buzzing Sound When Trying To Start-Fixed

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Trying to start your lawn mower and only getting a buzzing sound in return could be frustrating. This problem usually occurs after storing your lawn mower without use for a long time.

In this article, I talk about simple fixes that other lawn mower owners have used to solve their mower buzzing problem and an easy-to-follow guide for cleaning your lawn mower’s engine. 

Reasons Why Your Lawn Mower Makes A Buzzing Sound When Trying To Start

Your lawn mower making a buzzing sound when trying to start means that the starter mechanism is not properly engaging the engine, resulting in the buzzing sound.

This could occur as a result of one of the following:

  • Debris stuck in the starter gear
  • Loose/damaged battery cables 
  • Battery producing insufficient voltage
  • Damaged starter solenoid
  • Worn-out starter motor
  • Cracked/broken spark plug

Lawn Mower Makes Buzzing Sound When Trying To Start: Causes And Fixes

1. Debris Stuck In The Starter’s Gear

This is the most common reason your lawn mower makes a buzzing sound when you try to start it. As you mow with your mower, grass, leaves, and other foreign debris might get stuck in a part of the engine.

Mice also climb into the engine compartment and release pee/poop all over the area, gumming up the engine. This prevents the starting mechanism from functioning properly and produces a buzzing sound in the process.

Fix

  • Open up the engine compartment. 
  • Use a spray lubricant such as a WD-40 (preferably one with a spray nozzle) to blast the metal parts. This will remove all the debris and foreign materials.
  • Allow it to sit for a few minutes.
  • Close up the engine compartment and start up the machine.

2. Loose/Damaged Battery Cables

Due to frequent use, the wire cables that connect the mower battery to the starter motor can become loose or displaced. This can also affect the starting mechanism of the lawn mower.

Fix

Use a screwdriver to tighten all the cables connecting to the battery. Replace any displaced or damaged cable if found.

3. Battery Producing Insufficient Voltage

If after tightening the battery cables the problem persists, use a voltage tester to check if the battery is producing fewer volts than is required by the lawn mower. 

For a lawn mower to start, the battery needs to produce at least 12 volts. This is because the starter motor requires a specific level of power to start the engine. 

If the battery does not produce sufficient power (volts), the starter motor will not be able to completely ignite the engine and the lawn mower will produce a buzzing sound in the process.

Fix:

Replace or recharge the battery if the voltage it is producing falls below what the mower needs before attempting to start it again.

4. Damaged Starter Solenoid

The starter motor of the engine is powered by the starter solenoid, a small electromagnetic switch that is located inside the starter motor. 

A damaged starter solenoid will prevent your lawn mower from starting and create a buzzing sound. If this is the case, it is best to replace the starter solenoid.

How To Replace A Damaged Starter Solenoid:

  • Remove the battery
  • Remove the battery box
  • Remove the starter solenoid
  • Install the new starter solenoid
  • Reinstall the battery box and the battery

NB: When removing the starter solenoid, take note of the locations of all the wires connected to it. It might help to take a picture or draw a map before taking out the old one.

5. Worn Out Starter Motor

After checking and confirming that the starter solenoid, battery, and electrical connectors are all in good working order, the engine starter motor is most likely the source of the issue.

To start the lawnmower engine, the shaft of the starter motor rotates to engage the flywheel’s teeth. 

If the starter motor of your lawn mower is worn out or damaged, it will be unable to start and can cause a buzzing sound.

Fix:

The starter motor should be fixed or replaced with a new one. Fixing an electric starter motor requires professional experience therefore it should be left to a lawn mower technician.

6. Cracked/Broken Spark Plug

When the spark plug is attached to the engine plug either too tightly or improperly, a spark plug blowout occurs. 

As a result, the spark plug itself malfunctions and can no longer effectively transfer electric charge from the plug to the engine block.

Check the ends of the spark plug for rust or any visible damage. A cracked or broken spark plug can affect the start-up of your lawn mower and produce a buzzing sound.

Fix:

Install a new spark plug into the lawn mower’s engine. This is a very easy process and requires little to no technical experience.

How To Find And Clean Debris From A Lawn Mower’s Engine: Simple Steps To Follow

The most common problem that affects the starting motor of a lawn mower is grasses and debris getting stuck inside the lawn mower’s engine.

Here are simple steps you can take to effectively clean your lawn mower’s engine.

Step 1: Before you begin, turn off the engine of your lawn mower.

Step 2: Disconnect the spark plug while making sure the spark plug lead is kept clear and secure.

Step 3: Remove the metallic/plastic housing and air filter of the engine using the right tools. Use a small container to keep the screws and bolts safe.

Step 3: Clean the cooling fins, the flywheel compartments, blower housing, and other visible parts carefully using a small bristle brush.

Step 4: Apply a spray lube directly on the metal parts of the engine and wait for 10-12 minutes to break down dried-up grease.

Step 5: Wipe debris away with a neat cloth.

Step 6: Replace the metallic/plastic cover and return the screws to their respective positions. Tighten each screw with a screwdriver to prevent them from falling off.

Conclusion 

Carrying out a thorough assessment of your lawn mower’s engine can help you identify the reason it buzzes when trying to start. 

This reason could be a broken spark plug, the presence of debris, a damaged battery, a broken spark plug, etc.

Follow the recommended fixes in this article to solve the mower buzzing sound problem so you can get your lawn mower running again.