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How To Change The Throttle Cable In A Lawn Mower!

Written by William
Last Updated on August 31, 2021

Our Best Guide To Adjusting & Changing The Throttle Cable On a Lawnmower

The throttle on your mowers is one of the most essential parts as it ensures everything else is working correctly, especially the speed of the mower's engine and how fast the blades are cutting, when your throttle fails, you will need to change it or repair it, we have found the best way to do this through trial and error.

To change the throttle cable on your lawnmower is pretty simple and will not require you to take it to a professional. You will just need to ensure you have a screwdriver, pliers and a wrench for the process and adjust to the right clearance so your mower can work efficiently.

So as you can replace and adjust your throttle correctly, we have put together a guide that will tell you how to do this below, as well as why a throttle is so important on your mower and how they work.

Let's get fixing that throttle!

What Is a Throttle On a Lawnmower?

First, let's start by understanding what a throttle is on a lawnmower and how it works.

The throttle on your lawnmower is what allows you to adjust and control the speed of the machine, it does via a cable which is usually located by the intake valve of your carburettor.

On most modern lawnmowers, the throttle will come automatic, this means as soon as you switch the lawnmower on it will regulate the fuel and turn the blades to the adjusted speed, allowing you to get on with mowing without having to set the throttle manually.

For manual throttles on older mowers, you would have to adjust this manually for it to control the speed.

Symptoms Your Throttle Needs Adjusting

When your throttle starts to fail you will notice some common symptoms in your lawnmower such as it the speed being inconsistent or that the mower is cutting grass unevenly.

We have listed out some other symptoms below which might show your throttle needs changing/adjusting -

  • High fuel consumption.
  • Inconsistent cutting.
  • Engine cut-outs.
  • Takes a long time to mow the lawn.

Why Is The Throttle On My Lawnmower Sticking?

Another common problem that can occur with the throttle on a lawnmower is when it gets stuck, this will mean you don't have accurate or full control over the speed of your mower.

Some common sticking causes from the throttle on a mower are -

  • The throttle was exposed to extreme temperatures - Too cold or too hot temperatures could cause the throttle to get stuck and rust, on the mower.
  • There is dirt - If you have not been cleaning your lawnmower well then there is the potential for dirt to build up around the throttle of the mower and get inside, causing it to become stuck.
  • Bad maintenance - The area of your throttle should always be lubricated as part of your maintenance to avoid the throttle from becoming stuck.

Benefits Of Using a Throttle On Your Lawnmower

When operating a lawnmower, most people tend to have their throttle at half speed, as operating it at full is often unneeded and requires a lot of fuel consumption.

However, if you do decide to operate your throttle at full speed then it comes with some great advantages -

Helps The Engine Work Better

Using the throttle on your riding lawnmower can help the battery charge, as recharging the battery from the engine only occurs when the mower is performing at high enough RPMs, which requires throttle use. Running the mower at full throttle will also not lead to more fuel consumption than running at half as the engine will be lagging thus using more fuel to keep up.

Gives a Cleaner Cut

Due to the blades moving faster because of the full throttle, this helps give that professional and clean-cut to your lawn rather than tearing the grass or cutting it unevenly.

Operates At a Lower Temperature

Running the throttle at full speed on your lawnmower will additionally speed up the cooling fan and put the engine under much less stress when cutting. Opening your throttle to full-on inclines is important to stop the engine from overheating.

Can Handle Heavy Duty Grass

For tough terrains and dense patches of grass, letting the mower run at full throttle will help you cut these areas more efficiently. It also makes the lawnmower less likely to clog up during use.

How To Change & Adjust The Throttle On Your Lawnmower

Now we know everything about throttles and how they work on your mower, let's get on to how to change and replace the throttle if yours has become faulty.

We will list some steps below that will guide you through the changing process.

Tools Needed

  • Socket wrench.
  • Pliers.
  • Feeler gauge.


  • Step One - Remove the spark plug of your mower and start to disassemble the air filter on the mower, make sure to put the screws in a safe place and locate the governor's arm, in some models you may need to disconnect the fuel tank too.
  • Step Two - Set the throttle to the fast position on your mower and measure the distance between the choke level and control level, this should have around 1/40000 of an inch with a feeler gauge.
  • Step Three - If your clearance is more than this, you will have to change the throttle cable to be tighter, you can do this by loosening the cables bolt with a wrench and pulling it towards you until tight enough.
  • Step Four - Reassemble everything and check if the throttle is working how it should be now it has been changed.

Frequently Asked Questions About Changing The Throttle On a Lawnmower

Why does the throttle on my lawnmower keep becoming loose?

A throttle can keep becoming loose due to old age and loss of moisture, one way to prevent this from happening is by regularly lubricating it.

How do I adjust the speed of my lawnmower? 

To change how fast your mower is going you simply apply more or less pressure to the throttle on your mower.

What is the governor on a lawnmower?

The governor helps operate the automatic throttle on your mower and will keep the speed stable no matter the load on your machine, this means your mower will stay stable even on inclines or very tall grass.

Last Words

Overall, changing the throttle on your lawnmower is very simple and easy to do, just ensure you remove the spark plug and always put parts of your mower in safe places for re-assembly. If your mower still has inconsistent speeds after changing the throttle you may have to take it to a professional.

About the author
Written by William
I have always had a passion for gardening and that with a background in selling lawn mowers for the past 10 years, I have become very knowledgeable in all types of gardening tools. The site was created as a hub where I can review and write about all of the tips around gardening.
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