Lawn Mower’s Throttle: Here’s How it Works

What is a Throttle?

A throttle is what regulates the amount of air that gets into your air-fuel mix to determine the speed of your mower.

image of mower throttle

This means it does not really change the speed of your mower, rather the airflow that eventually determined how fast your engine runs.

While most people are used to running it partially, it benefits your mower to run at full throttle.

A throttle is located in a carburetor’s intake butterfly valve. Most of the modern ones have automatic throttles, though.

A carburetor is what delivers the mixture of gasoline and air to the combustion engine to it regulates the speed at which it moves.

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Typically, a carburetor has two butterfly valves. One of them, the choke, controls the amount of air that mixes with the gas. The other one controls the amount of the air and gas mixture that is fed in the combustion chamber.

This amount is usually determined by the task at hand, for example when working on a grassy hilly terrain, or on wet grass, the valve will automatically increase the engine’s output.

Why Run your Mower at Full Throttle?

There are several benefits associated with this.

1. The Engine is Stressed Less

Three things cause the engine some serious stress; an undercharged battery, poor vibrations/shakes, and fuel use.

Your mower’s engine is designed to run at full throttle and so running it partially can cause it to consume more fuel because it will lug.

When this happens, the cylinders are likely to be drained of lubricating oil, which then shortens the life of cylinders and pistons and consumes more fuel.

picture of kohler mower engine

There is also likely to be a change in vibrations as an engine vibrates differently when running as full throttle. At half throttle, it shakes differently, in the process causing equipment failure.

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Running at full throttle is good for your battery too. Some batteries do not start to recharge until they have reached a certain RPM, and so you want to ensure you are helping yours revolve as many times as possible.

The battery is drained on ignition, and so the faster it can run, the sooner it recharges.

2. The Mower Stays Properly Temperature

When more air is pushed into the engine, it regulates its temperature, which is necessary to prevent overheating. Hydro-static transmissions usually produce heat when in use, and so they need a fan to keep them cool.

An engine running at full throttle ensures enough airflow to keep everything at the perfect temperature.

3. It Cuts Cleaner

If you want a clean-cut lawn, then you want the blades to spin at higher velocity, which only happens when it runs ate full throttle. At higher velocity, the blades will cut swifter, leaving your lawn evenly cut, which is what we all want.

Why a Lawn Mower Throttle may stick in One Position

The throttle, choke lever, throttle arm or throttle linkage may fail to work at some point, and it is important to fix them as soon as possible to have your mower up and running in time for the mowing season.

You can only fix something when you know what is wrong, and so these are the common culprits when it comes to the throttle.

1. Exposure to the Elements

Poor weather conditions – too cold, too much heat, and moisture – are enemies of a mower and its components, and they will always get to it if storage is poor.

If any of the parts is rusty due to exposure, you want to restore them before resuming usage.

2. Poor Maintenance

illustration of tools

As a lawn mower ages, the throttle casing may lose its tightness, exposing the throttle to loss of moisture and lubrication.

You can prevent this from happening with a spray-on lubricant that keeps the components well-moisturized each season.

3. Dirt Around the Throttle Area

If you leave your mower unattended off-season, dirt could accumulate around the throttle to expose the insides adversely when it is opened. You want to clean this area first before opening the throttle casing to prevent any of the dirt from making its way inside.

Curious to know how your mower throttle works?

Final Word

A lawn mower’s throttle is an important part of it, and you want to check it regularly, even off season, to ensure it is in perfect condition.

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