How to Fix a Lawn Mower Throttle Cable

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Is your lawn mower dying down whenever you use the throttle or not starting at all? Your throttle cable may be responsible for this. The cable may be bad or broken, which means it needs special attention right away.

But before you start to panic, replacing or fixing a lawn mower’s throttle cable is not difficult at all. You can get it all done within a few steps,  without any mechanical skill or experience. This article talks about exactly how to fix a lawn mower throttle cable in simple steps. Keep reading to find out.

What Does the Lawn Mower Throttle Cable Do?

Although it is a very small component of the lawn mower, the throttle cable performs a very important role in the mower. It is what controls the speed of the engine, and determines how fast the blades move when you’re mowing your lawn. Learn more about how a lawn mower throttle cable works.

When the cable is bad or broken, it causes the mower to be less efficient, and in some cases, refuses to even start.

While some mowers have manual throttles, the most modern ones come with an automatic throttle. With such a mower, the throttle automatically adjusts itself based on the task at hand.

My Lawn Mower’s Throttle Cable Does Not Work. What Could Be Wrong?

There are a couple of reasons this is happening. You just need to carefully observe the cable to rightly diagnose why it has refused to work. The first place to start is to check if the cable is broken. 

So pull it out of the outer tube and check through its entire length to see if it’s broken in any part.

If the cable is broken somewhere in the middle, then, you will just have to replace it. If it’s just the z-tip that’s broken, simply getting a new z-tip will fix the issue.

However, if the cable is not broken but still won’t work, then that’s not a big issue. It could just be that the cable is stuck somewhere – usually when dirt has entered the outer tube or the inner cable is already getting rusty.

In that case, get some WD-40 and spray it on the cable a couple of times. That should get your throttle cable to work perfectly again. But if it still won’t work, you may need to replace the cable.

Why Does a Lawn Mower Throttle Cable Break

Why Does a Lawn Mower Throttle Cable Break?

Although many factors could be responsible for the breakage of your throttle cable, the most popular is due to wear and tear. 

As you use your lawn mower over time and the cable constantly comes under pressure, it begins to wear out or get stretched, resulting in breakage.

When the throttle cable is broken, you might start experiencing a delayed response from the throttle. 

Sometimes, the lawn mower’s engine may refuse to start. Whenever you start noticing these signs, then it’s time you consider changing the throttle cable.

How to Fix a Broken Z-Tip of a Lawn Mower Throttle Cable

Before you begin fixing your broken z-tip, get all the tools you will need in one place. You will need a z-bending tool, some measuring tools, a new throttle cable, a needle nose plier, and wire cutters. 

Once you have all of these, then you can go ahead with the steps below to get the job done.

Step 1: Prepare your cable

Get a 7-inch #16 wire size cable and bend it in half. Aluminum cable is always recommended for this because it is easier to turn and twist than any other type of cable. 

Once you have the aluminum wire, use the pliers to flatten it, and press the two bent halves together.

Step 2: Create the Z-bends

Here, you will be creating two z-bends – one on each end of the wire. To do this, use a wire flattener or nose pliers to hold the bottom of the wire by two inches. 

Now, get any device that can hold a #16 wire in an upright position so you can twist the free length of the wire a couple of times.

Twist the wire enough, while being careful not to break it. Bend the top of the wire at a 90-degree angle using the plier so it can create a z-bend on the wire. 

Now, use a couple of needle-nose pliers to hold firm the first 90-degree bend while you try to make the second 90-degree angle on the other end.

To make this easier, you can check the z-bend of the original throttle cable and try to copy it instead of going through this step.

Step 3: Cut off the z-bend end of the wire

The next thing is to snip off the z-bends of the aluminum wire.

Step 4: Combine both throttle cables

Combine the z-bend of the aluminum wire you just created and combine it with the old throttle cable. 

Put the z-bend just below the original wire on a table in such a way that both of their z-tips are parallel. Now use a marker to mark the part you need to cut.

Step 5: Cut the cable

Now that you have made the mark, cut the original cable just at the point you mark. 

For the z-bend of the aluminum wire, cut off another extra 1-2 centimeters from the marked point.

Step 6: Replace the z-tip of the original cable

Use a wire union device to carefully merge the original throttle cable and the z-bend aluminum wire. 

You can also use a hammer if you don’t have a union device. Now, you have just successfully fixed the broken z-tip of your lawn mower throttle cable.

How to Replace a Broken Lawn Mower Throttle Cable

If you notice the throttle cable is broken, the best solution is to get a new throttle cable to replace the damaged one. 

You can easily get this online or at a nearby hardware store. Once you have gotten a new cable, follow the steps below to fix it on your lawn mower.

Step 1: Remove the broken throttle cable

Turn off your lawn mower and use a pair of needle-nose pliers to gently remove the cable casing at the base of the mower. 

If you don’t have a plier, you can use your bare hands to twist off the screws too.

Lose the throttle cable from the throttle arm by opening the unit and gently removing the screws on the handle.  The throttle cable would be free once you unscrew the handle. Then, you can pull it out.

Step 2: Install the new cable on the handle

Check the back of the engine for the wire base. Now, insert the new cable through the base and the throttle arm. 

Use a bolt to fasten the new cable. But if there are no holes there to hold the bolt, you may need to drill new holes.

Step 3: Connect the new cable

Measure out the length of the throttle cable you think will fit and give it a little extra inch for allowance. The purpose of the extra allowance is to make the cable loose enough to allow the handles to be folded all the way down.

Now, slip the new cable through the casing and fasten it to the throttle handle. Make sure it is tight enough for you to have the throttle all the way down. 

Tighten the lock screw and reinstall the casing.

Step 4: Adjust the new cable

Now that the new cable has been installed, you need to check if the tension on the throttle is not too much. 

So, turn on the mower and observe its behavior. If it is running too high even while at a spot, it means the tension on the cable is too much, and you will need to loosen it.

Loosen the lock screw a little and slide a bit more cable through the slot. Then, tighten the screw again.

Step 5: Try to drive the lawn mower

Check if your new throttle cable is working fine by doing a test drive. Try to drive your lawn mower to see if the engine is now responding well to the throttle.

Why Do I Need to Operate the Throttle At Full Speed?

One major sign that your throttle cable is bad is that the engine will not be able to operate at full throttle. The engine begins to die down whenever you try to go on full throttle. 

While some users may prefer to operate the mower at partial throttle, there are lots of benefits associated with going at full speed. 

Let’s take a look at some of these benefits:

#1: Full throttle puts less stress on the engine

The engine of your lawn mower is designed to operate at full throttle. Going anywhere less can stress the engine parts and reduce its efficiency over time. 

It can shorten the life of the battery because certain engines won’t begin to charge the battery until they reach a particular RPM level, which may require that you go on full throttle.

#2: It makes the engine use less amount of fuel

Contrary to popular belief, full throttle makes the engine use less fuel than when it’s run on partial throttle. At full throttle, the engine runs at its best, hence reducing the amount of oil used for its operation. This is usually the other way round when it’s running on partial throttle.

#3: It will give your lawn a cleaner cut

The blades of your mower move at the best speed at full throttle because the engine is also running at its best during the time. 

Important to note that faster blades mean a better cut, hence giving your lawn a perfect finish.

#4: Your mower keep cutting even in heavier grass

There is no better way to bring down those heavy grasses around your lawn than to run your lawn mower at full throttle.

 It will make the job easier for you and the mower. But when it’s run on partial throttle, the heavy grass clogs up in your mower, which may require you to do the cutting manually.

Final Note

A broken throttle cable is inevitable and every lawn mower owner should expect it. However, when it eventually happens, it is nothing to panic about. 

Fixing a throttle cable is not difficult – in a couple of steps, you will be done with the whole procedure.

We have given detailed steps on how to fix your throttle cable in this post. If you are, however, confused about the location of any of the parts mentioned, you should always consult the user manual.