Common Lawn Mower Ignition Switch Problems And How To Solve

Hello there!

Encountering issues with the ignition switch can be frustrating while mowing your lawn. So, you need to find a way to fix it. 

There are multiple lawn mower ignition switch problems. This guide will show you how to tell if the switch is faulty and recommend practical solutions. Don’t miss out on the valuable insights that await you – let’s keep reading!  

A Lawn Mower Ignition Switch: How Does It Work? 

Before dealing with problems with your lawn mower ignition switch, you should first understand how it works. The working process of this system is as follows:

  • Turn the key to the “Start” position. This step sends a signal to the ignition system.
  • The system powers the coil through a white wire. 
  • The coil closes its contact in the solenoid.
  • Power runs to the black wire through the red wire. 
  • The start motor rotates to crank the engine and start your lawn mower. 
  • Turn the key to the “Run” mode so the engine can keep running. 
  • Turn the key to the “Off” mode to cut off the power. 

Besides, the ignition switch handles electrical functions. Here are some lawn mower ignition switch letters to learn: 

  • L for Lights
  • M for Magneto
  • S for Starter Solenoid
  • A for Accessory 
How To Know Lawn Mower Ignition Switch Problems?

How To Know Lawn Mower Ignition Switch Problems? 

A good lawn mower should run once you turn on the ignition switch. If not, perform these tests to tell if the switch is malfunctioning. 

Starter solenoid test

You can test the start solenoid by following these steps:

  • Place the key into the ignition switch.
  • Connect the negative terminal of a multimeter to the distributor’s base, and the positive terminal goes to the power supply. 
  • Turn the key to the running mode.
  • Check the reading on the multimeter. It should be at least 90%. You may have problems with the wiring or the ignition switch if it’s lower.

Warning light test

The warning light test involves these steps: 

  • Insert the lawn mower key into the ignition switch, then turn it to the “Start” mode. 
  • Release the key once the engine begins cranking, allowing it to automatically return to the “Run” mode.
  • Now, pay attention to the warning lights. If they turn off, the ignition switch may become faulty.

Magneto test

You can also check for your ignition switch issues by trying this magneto test:

  • Set your multimeter to “ohms.”
  • Switch the key to the “Off” mode.
  • Test for continuity by checking the connection between the magneto terminal (letter M) and the ground terminal (letter G).
  • If you hear a beep, the component is working correctly. And if not, you may be experiencing potential magneto failure.

How To Start A Lawn Mower With A Bad Ignition Switch?

If your lawn mower has a bad ignition switch, you have two options:

Option 1: Fix the issue

Wiring is among the most common issues with your ignition switch. If your lawn mower runs and then suddenly stops, the wire connections can be the cause. So, check for loose wiring that could hinder the current flow to the solenoid.

A disconnected ground terminal can contribute to the problem, too. Hence, remember to examine the ground terminal of the switch.

Another issue is with the malfunctioning ignition coil. The faulty coil can’t properly spin the flywheel. Sometimes, it can still be good but fails to spark. As a result, the crankshaft won’t engage. 

In this case, you need to replace the ignition coil:

  • Remove the spark plug and ensure it touches the engine block. 
  • Start your engine and wait for sparks. If you don’t see any, the ignition coil needs replacement.
  • Access the ignition coil while disconnecting the lawn mower coil kill wire attached to it. 
  • Install the new ignition coil, reconnect the kill switch wire, and loosely screw it in place.
  • Create a small gap between the ignition coil and the flywheel magnets. 
  • Tighten the screws. 
  • Reassemble all the parts and start the lawn mower to check if the new ignition coil can work.

Option 2: Replace the switch 

If your ignition switch is damaged severely, you must replace it. So try these steps to do it properly:

  • Start by disconnecting the battery to ensure safety during the replacement process.
  • Find your ignition switch, then remove it. You need to remove any bolts or screws that secure it. 
  • Carefully disconnect the wire harness connected to the ignition switch. 
  • Take the new ignition switch and position it in the same location as the old switch. 
  • Secure the new switch with the appropriate screws or bolts.
  • Join the wire harness with the replacement ignition switch, connecting it to the corresponding terminal. 
  • Reconnect the battery by attaching the battery. 
Ignition switch

Tips For Avoiding Lawn Mower Ignition Switch Problems 

The lawn mower ignition switch may break down for some reason. Here is what you should do to protect it:

  • Choose lawn mowers and components from reputable brands known for their quality and reliability. Buying high-quality products can reduce the likelihood of ignition switch problems.
  • Don’t ignore any small engine problems with your lawn mower. Instead, address them promptly to prevent further damage to the ignition switch. 
  • Test the switch regularly to ensure it’s still in good condition. 
  • If you notice corroded terminals, clean them with sandpaper and a wire brush to ensure smooth electrical conductivity.


1. What causes the ignition switch to fail?

There are multiple reasons for your ignition switch to fail, such as:

  • Improper installation
  • Temperature extremes
  • Broken string
  • Forcefully preventing the lawn mower from starting 

2. Can an ignition switch be repaired?

Yes. Depending on the specific issue, you can do some simple repairs to recover it. Yet, in severe cases, you must replace the faulty ignition switch. 

3. How long does an ignition switch last?

The ignition switch can last for several years. However, its lifespan varies depending on its quality, usage, and maintenance. 

It would be best to check the switch regularly and address any issues promptly. Then, it can work better and longer. 


We hope this article has provided valuable insights and practical solutions to tackle lawn mower ignition switch problems. Remember, a properly functioning ignition switch is the key to a smooth mowing experience. 

So go ahead and take action to enjoy your happy mowing time. For any further information, don’t hesitate to ask. Thank you for reading!

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