3 Ways To Bypass A Lawn Mower Key Switch

Generally, a normal push mower doesn’t include the ignition switch like riding lawnmowers. So, here we will mostly discuss about the key switch of a riding lawnmower. 

A key switch helps to create a connection between the starter and the solenoid, which causes the gear wheel to rotate and the engine to ignite.

If your lawnmower has a defective key and it’s not working even after so many tries, bypassing a lawnmower key switch is the only option to ignite the engine.

To bypass the key switch in a lawn mower, use a jumper cable and connect it to the correct poles of your mower’s battery and try starting the engine. Another common method is bypassing your mower’s hot wire/kill switch. However, you should only use this method if you know what you are doing.

In this article, you will learn how to bypass the key switch on your lawnmower and the method to check a missing or broken ignition switch. 

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What is the motive of a lawnmower key switch?

The key switch’s main motive is to ignite the lawnmower’s engine with the help of an electric connection. 

It is also in charge of switching off the engine if you are not operating the machine. 

The key switch is generally located in the control panel of a riding lawnmower. 

But if the ignition key doesn’t work, you will have to fix it. 

Bypassing a key switch is a temporary solution until you change the ignition switch completely. 

Signs of a faulty lawnmower key switch

If your lawnmower’s engine is not starting even after so many tries, it might happen because of a defective lawnmower key switch. 

Sometimes the key switch doesn’t work, and we think our lawnmower is facing some issues. Let’s discuss the signs:-

  • The Key is not moving: If the Key fails to turn on completely and remains stiff even after so many tries, something is wrong with the key switch. 
  • The wire is overheating: It is one of the common problems faced when the key switch is defective. You will notice one wire edge is extremely overheated.
  • Lawnmower stops suddenly: If the lawnmower suddenly stops while working, you might have a defective key switch.
  • The engine refuses to start: If you try hard to start the engine, it still fails every time. Then your lawnmower may have a broken and faulty key switch. 

How to check a broken lawnmower key switch?

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You must check the ignition switch frequently to see whether it works properly. 

If you notice that your riding lawnmower key switch is facing some issues, you can check it with the help of 3 ways.

 Let’s discuss the following:-

1st way to check

  • Take out the fuse panel and unlock it. From the panel, find the starter fuse and inspect the condition of the metal strip. 
  • If the metal strip is in poor condition, then immediately replace it with a good one. But the new metal strip amp should be the same as the old one. 
  • Bring a multimeter device and attach it to the negative and positive ends located on the battery. Inspect to see voltmeter red lead is attached to the battery’s positive (+) side.
  • The voltmeter should show at least 12.60V when the engine moves at full strength. But when it drops less than 12V, the battery is expired.
  • To see the condition of the key switch, put the Key on the switch and turn on the engine. If the engine doesn’t start and you don’t get any beeping sound from the device, the key switch is defective. 
  • But if there is a beeping sound and the engine doesn’t turn on, something is wrong with the battery, not the switch.

2nd way to check

  • Change the current sparkplug with an old one and put the Key into the switch to turn on the engine. The switch is defective if you don’t notice any spark on the old spark plug while turning on the engine. 
  • If unsure, you can also attach the voltmeter to the positive side of the coil and the battery’s negative end. The key switch is fine when the battery’s voltage is positive. But if it shows negative, the Key is defective. 

3rd way to check

This method is mostly for those people who are new to this. Let’s discuss the steps:-

  • Get the multi-tester device and connect the negative end on the bottom of the distributor and the positive end with the power supply. 
  • Put the Key on the switch and check the battery’s voltage with the help of the multi-tester device.
  • If the voltage is less than 90, then there is a high probability that your ignition switch is defective.

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Safety measures to follow for bypassing a lawnmower key switch

To bypass a key switch, make sure you follow some safety measures:-

  • Wear good quality rubber coated and mechanic’s gloves to prevent you from battery acid, heat, and electric shock.
  • Also, get safety glasses for protection from the battery spark that might come. 
  • Don’t wear any jewelry made up of metal; otherwise, it can connect with the battery cables. 
  • Also, wear a full-sleeved shirt, long pants, and shoes for extra protection. 

How to bypass a lawnmower key switch

All riding lawnmower has a key switch. 

So, here we will learn about bypassing the key switch on a riding lawnmower. 

There are in total 3 ways. Let’s discuss each way in detail.

1. Bypassing the key switch by using jumper cables

Even the most expensive riding lawnmowers can have a defective key switch. 

But you don’t have to worry about it.

This is one of the simplest ways to bypass the lawnmower key switch with the help of jumper cables. 

This is the same as jumping a car with cables, but it’s a bit different in the case of a lawnmower.

Tools required

There are 2 ways to bypass the lawnmower key switch with jumper cables. Let’s discuss both of them:-

Type 1

First, before you start, keep the lawnmower on the brake at a flat surface and remove all the connections with the battery. Also, make sure the blade is inactive. Now let’s begin:

  • Detach the hood to uncover the lawnmower’s engine. 
  • Then, again detach the cover of the black battery.
  • Look for the signs on the battery. A positive end shows (+), and a negative end shows (-). 
  • After that, grab your pliers or wrench, and unbolt the screws of the clamp that holds the negative terminal. 
  • Then remove the clamp from the negative terminal. 
  • The same procedure goes for the positive terminal. Unbolt the screws and remove the clamp from the positive terminal.
  • Then connect the jumper cables according to the numbering. The black cable needs to be connected to the negative (-) end, and a red cable needs to be connected to the positive (+) end.
  • After the jumper cables are attached, the riding lawnmower will start. Let the engine run for 1 minute, and then you can use it.
  • You can turn the lawnmower engine off and disconnect the jumper cables. 
  • Reattach the cover of the battery and the hood. 
  • If you want to start the engine again, you must do the same procedure. 

Type 2

This is the 2nd method you can follow for bypassing the lawnmower key switch with jumper cables. 

  • Wear rubber gloves properly. 
  • Keep the brakes ON and the blade inactive. Also, ensure you follow every safety measure so the lawnmower won’t move until and unless you release it. 
  • Then, uncover the lawnmower’s hood and look for the battery. 
  • If you see any red and black wires, then detach them from the 2 electrical poles in the solenoid. 
  • Then take the battery post cleaner and clean all the corrosion and dirt on both poles. 
  • Reattach the cables.
  • Fix the black wire over the lawnmower’s negative (-) battery post, and fix one more end to the deck made of metal on the lawnmower. 
  • Then, fix the red wire to the positive (+) battery pole and connect one more end with the metal piece on the lawnmower’s starter.
  • If the engine starts, you can detach the red and black wires and then cover the lawnmower’s hood.

2. Bypassing by hot wire procedure

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This is another method to bypass the key switch of a lawnmower. First, take out the key switch from the lawnmower if it is defective. 

Then you will see a 5-plug round metal pin just behind the key switch. You must be careful while doing this method because it requires a wire to bypass the lawnmower key switch. 

With the help of the hot wire, you can ignite the engine without the ignition switch. This method is also common for bypassing the key switch of the lawnmower. Now let’s discuss the steps:-

  • First, grab 2 wires and roll them together. Then, roll the wire edge over the screwdriver. 
  • When the engine is off, take 1 wire opposite the (+) terminal and connect another wire with the starter. Then, you will notice the engine has started.
  • After igniting the engine, take the wire to the (+) terminal. After the wire has become hot, detach another wire from the starter. 
  • If the lawnmower’s engine suddenly stops by any chance, shut off the engine and repeat the whole process. 
  • Then on the negative terminal, redo the same procedure. 

3. Bypassing by using a toggle/kill switch

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A toggle/kill switch is a tiny gadget used to power the circuits on and off. 

The kill switch includes 2 metal poles which should attach by a cord. 

If you turn over the switch, it will complete a circular path, and the electricity will start to flow.

This is also one of the easiest ways to bypass the lawnmower key switch. 

You will require wires and one toggle/kill switch. 

It is available in any hardware-selling store, so you can easily get it. Now, let’s discuss the steps:-

  • First, detach the riding lawnmower’s seat and then the covering to access the wire, which helps power up the riding lawnmower. 
  • Then, grab your wrench and detach the wires. If you are having difficulty in doing this, you can get professional help. 
  • Take the wires and remove the plastic cover of the wire from the end to uncover the metal inside. To do this, you will require strippers or pliers. 
  • Then attach the wire end to the toggle/kill switch. You must attach the wire to the switch holes and roll it properly. 
  • Then, re-connect the wires again to the riding lawnmower. Reattach the red wire to the (+) terminal and the black wire to the (-) terminal. 
  • Cover and attach the lawnmower’s seat. Now you can start the riding lawnmower with the help of the toggle/kill switch.

Final words

Bypassing your lawnmower is easy. You need to have proper knowledge of how to do that. 

There are 3 ways to bypass the lawnmower, i.e., by jumper cables, toggle switch, and hot wire. 

But if you are still unsure how to bypass the lawnmower key switch, you can get help from professionals. 

Also, you should frequently check whether the key switch is working properly. Otherwise, you may blame the engine or the battery for the issues. 

Bypassing the lawnmower key switch or replacing it. Which is better?

Bypassing a lawnmower key switch is a temporary solution to start the engine. 
It is always better to replace the lawnmower key switch with a permanent solution rather than bypass it every time. 

Can you bypass the lawnmower safety switches?

Yes, you can bypass the lawnmower safety switches if you want. Safety switches are given for operational protection. 

Reference: Lawn Mower Technology, Lawn Mower SafetyLawn MowingLawn CareMowing your lawn.


Hello everyone, My name is Richa and I am here to make you a better gardener by creating an in-depth and helpful resource for all the fellow gardeners out there. If I could help even a few people understand their plants better then I call it a success for my efforts.

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