Your Complete Guide to Fixing A Broken Lawn Mower Throttle Cable


Jeffrey Tung on Apr 12, 2024

Hand on lawn mower throttle cable

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Throttle cables are a vital component of your mower's engine control system. But like any mechanical part, they can wear out or break over time. 

When this happens, it can be overwhelming - especially if you need to get back to mowing soon. I know many of us have never tried to fix a lawn mower throttle cable before. 

But don't fret!

This article will break down everything you need to know about throttle cable, so you can start the mower and get it back in action. 

What is a mower throttle cable?

The mower throttle cable is the part that connects the throttle arm to the engine. It runs alongside the mower handle. 

When you push the lever, it pulls or releases the cable, adjusting the position of the throttle valve in the engine. This valve controls the airflow into the engine, determining the mower's speed and power output

Simply, the throttle cable is the direct link between your hand's movement and the engine's performance. Without it, controlling your mower's speed and output is practically impossible.

What are the signs of a damaged lawnmower throttle cable?

Detecting a faulty or damaged throttle cable is essential in maintaining your mower and preventing a cascade of issues that can stop you from doing lawn care. Keep an eye out for these telltale signs.

  1. Resistance when using the throttle. Pushing the throttle lever on your mower's handlebar should be easy. If you feel stiffness or experience any resistance, it could be a sign of internal damage to your cable.
  2. Erratic engine speed. As previously said, the throttle cable is responsible for helping you control the speed and power of your engine. So if you notice fluctuations in performance, it may indicate cable issues. 
  3. Fraying or kinks on the cable. Damage to the cable's outer casing can expose the inner wire to moisture, dirt, or debris. This can accelerate corrosion and compromise your cable's performance. 

What causes throttle cables to break?

Over time, throttle cables can get damaged because of regular use. However, there are times they fail because of other reasons. Some common causes include prolonged exposure to debris or moisture or excessive cable tension or stress. Manufacturing defects or poor maintenance practices can also contribute to cable failure

Common issues to fix on lawn mower throttle cables?

1. Stuck cable

A stuck cable occurs when it binds to its housing, preventing smooth movement. This may be caused by the build-up of rust or dirt within the cable housing. 

Fortunately, fixing it is pretty simple.

  1. Remove the cable from the mower gently.
  2. Check if there is any debris or dirt that may be causing the cable to get stuck. Remove.
  3. Place the cable in a container and soak it in a suitable lubricant or penetrating oil overnight. A WS-40 or silicone spray works.
  4. Gently work the throttle lever back and forth several times until you free the cable. 
  5. Reconnect the cable back into the mower. Check if it's working. 

2. Loose cable 

A slack cable occurs due to improper adjustment or excessive stretching. This causes reduced responsiveness and control over the engine. 

Here's how you can fix this problem.

  1. Remove the cable from the mower.
  2. Locate the adjuster which is usually located near the throttle lever.
  3. Unfasten the nut securing the adjuster in place.
  4. Turn the adjuster clockwise to increase cable tension.
  5. Make sure the cable is tight but not too much.
  6. Tighten the nut once the desired tension is achieved.

How do I repair the throttle cable?

Sometimes, the issue with throttle cables goes beyond a loose or stuck cable. If it breaks, here's what you can do save some dollars.

Tools Required

  • Pliers
  • Screwdrivers
  • Lubricating oil 
  • Aluminum cable
  • Wire cutters
  • Aluminum crimp

Step 1: Check the damage.

Examine your cable to determine the extent of damage. If it's severely damaged, it's best to replace it entirely. However, if the damage is minimal, you'll be able to repair it. 

Step 2: Make the Z-bend.

Get a 7-inch aluminum cable and bend it in half. Flatten it using a pair of pliers. After both halves are flat against each other, secure them between two sturdy objects. Twist the wires together then copy the Z-bend of the original cable by bending the top of the wire at a 90-degree angle. Hold the first 90-degree bend with needle nose pliers as you bend the other end to create another 90-degree angle. 

Step 3: Join the cables.

Once this is done, place your original cable parallel with the Z-bend wire you just made. Use a marker pen to mark where you'll need to cut the wires. Trim as needed. Insert the original throttle cable into one hole of the aluminum crimp and the Z-bend wire into the other. Tighten the device to secure both wires in place.

Step 4: Reinstall the cable.

Reinstall the throttle cable on your lawn mower and make sure it's routed correctly and securely attached at both ends. Start the engine and test the throttle control. Pay attention to any signs of sticking or binding.

If all is good, pat yourself on the back. You've just repaired your throttle cable. 

If the throttle is unfixable, how do I replace and adjust it?

If you feel your mower is damaged beyond repair, don't worry. Replacing it is much simpler than you think. It's a perfect DIY project even for beginners. 

Here's how to do it.

Tools Needed

  • Socket wrench
  • Pliers
  • Screwdriver
  • Replacement cable

Step 1: Remove the old cable. 

Loosen the cable from your lawnmower. Use pliers to disconnect it from the throttle lever and any other attachments. Trace the cable down to the engine and disconnect it from the carburetor.

Step 2: Install the new cable.

Make sure you are using the right cable by checking the manual or serial number on your old cable. When installing the new cable, you may need a drill if there are no holes yet and a bolt to fasten the new throttle cable. This will depend on your mower’s original throttle and design.

Take your new cable and feed it through the same path as the old one, making sure it follows the same route and is properly aligned. Attach one end of the cable to the throttle lever on the handle using your pliers. Then, thread the other end of the cable into the engine compartment and connect it to the carburetor. 

Step 3: Calibrate the cable tension.

Once the cable is installed, you may need to adjust the throttle cable tension to ensure it's working properly. Use your screwdriver to loosen or tighten the adjuster. 

Step 4: Test the mower throttle cable. 

Give your mower a quick test. If it's running too high in idle, loosen the cable. Twist the lock screw a little and slide a bit more cable through the slot and secure the screw. 

Final thoughts

Maintaining a properly functioning throttle cable is essential in lawn mower care. By recognizing the signs of damage, addressing common issues, and knowing how to repair or replace them, you can extend the life of your mower and save unnecessary expenses.

If you wish to learn more about lawn mower maintenance, read our article here.