Where Should the Throttle Be to Start a Lawn Mower?

The warm weather is here, and you’re ready to tackle your lawn. You grab your trusty mower, give it a pull, and…nothing. Frustration mounts as you tug again and again, wondering if your mower is even going to cooperate. Maybe you’ve even checked the gas and oil, made sure the spark plug is in good shape, and still, nothing. The problem might be as simple as your throttle setting.

This article will explore the proper way to set your lawn mower throttle for a successful start, covering different types of mowers, common mistakes, and troubleshooting tips. So, grab your lawn mower, and let’s get started!

A Quick Answer

In most cases, you should start your lawn mower with the throttle in the “choke” or “fast” position. This ensures the engine gets a rich fuel mixture and ignites easily. Once the engine is running, you can gradually move the throttle to the desired speed.

Understanding Your Lawn Mower’s Throttle

Before we dive into starting your mower, it’s important to understand the different parts of the throttle system and how they work together.

Throttle Control

This is the lever or knob you use to adjust the engine speed. It can be located in various positions on your mower, but is most commonly found on the handle or side of the engine.

Throttle Cable

A cable connects the throttle control to the carburetor. As you move the throttle, the cable pulls or releases a valve in the carburetor, controlling the amount of air and fuel entering the engine.


The choke is a device that restricts airflow to the carburetor, creating a richer fuel mixture. This is important for starting the engine as it helps ignite the fuel more easily.

Starting Your Lawn Mower: A Step-by-Step Guide

  1. Check the Fuel and Oil: Always ensure your mower has enough fuel and the appropriate oil level before starting.
  2. Set the Throttle: Before you start your mower, set the throttle in the “choke” or “fast” position. This ensures a rich fuel mixture for easy starting.
  3. Prime the Engine (If Necessary): Some mowers have a primer bulb. If yours does, press it a few times to manually add fuel to the carburetor.
  4. Start the Engine: Pull the starter cord firmly and consistently until the engine starts.
  5. Adjust the Throttle: Once the engine is running, slowly move the throttle to the desired speed. You might need to adjust the throttle slightly depending on the load (mowing, idling, etc.).

Common Throttle Starting Mistakes and Troubleshooting

Even with the best intentions, starting a lawn mower can sometimes be frustrating. Here are some common mistakes and troubleshooting tips:

1. Not Using the Choke

If you’re trying to start your mower without the choke engaged, you might be starving the engine of fuel, making it difficult to ignite.


  • Make sure your choke is properly engaged.
  • If you’re unsure, consult your owner’s manual for the correct position.
  • If the choke is in the correct position and the engine still won’t start, consider checking your fuel lines and carburetor for blockages.

2. Throttle Set Too Low

While it might seem like a good idea to start the engine at a low speed, it can actually make it harder to start. A low throttle setting can lead to a lean fuel mixture that won’t ignite properly.


  • Start with the throttle in the “choke” or “fast” position.
  • Gradually reduce the throttle once the engine is running smoothly.

3. Engine Flooding

If you’ve tried starting your mower multiple times without success, you might have flooded the engine with too much fuel. This can happen if you hold the starter cord too long or keep the choke engaged for too long.


  • Allow the engine to sit for a few minutes to allow the excess fuel to evaporate.
  • Remove the spark plug and dry it with a clean cloth. This helps remove any excess fuel that may have accumulated in the cylinder.
  • Reinstall the spark plug and try starting the engine again.

4. Clogged Air Filter

A clogged air filter can restrict airflow to the engine, making it difficult to start.


  • Inspect your air filter regularly and clean or replace it as needed.
  • A dirty air filter can also cause your engine to run poorly, so it’s important to maintain it.

Throttle Tips for Different Types of Mowers

While the general process for starting a lawn mower with a throttle is the same, there might be some slight variations depending on the type of mower you have.

Push Mowers

  • Most push mowers have a single throttle control lever located on the handle.
  • Set the lever to the “choke” or “fast” position before starting.
  • Once the engine is running, gradually move the lever back to the desired speed.

Riding Mowers

  • Riding mowers typically have a throttle lever on the dashboard or near the steering wheel.
  • Engage the choke, start the engine, and then gradually reduce the throttle to the desired speed.

Robotic Mowers

  • Most robotic mowers have a dedicated “start” button and don’t require throttle adjustments.
  • However, some models might have a variable speed setting, which you can adjust using a control panel or app.


Starting a lawn mower can be a straightforward process, but understanding your mower’s throttle system and common mistakes can save you time and frustration. Remember to always check your fuel and oil levels, use the choke properly, and adjust the throttle gradually. With a little practice and patience, you’ll be ready to tackle your lawn with confidence!

Frequently Asked Questions

What is the throttle and what does it do?

The throttle is a lever or knob on your lawn mower that controls the engine’s speed. When you push the throttle forward, it opens the carburetor’s butterfly valve, allowing more air and fuel to enter the combustion chamber. This results in a faster engine speed, and consequently, a faster blade rotation. Conversely, pulling the throttle back reduces the airflow and fuel mixture, slowing down the engine.

Understanding the throttle’s function is essential for safe and efficient lawn mowing. It allows you to tailor the mower’s power to the task at hand, whether you’re tackling thick, tall grass or simply trimming the edges of your lawn.

How do I know where to set the throttle for starting?

The correct starting position for your lawn mower’s throttle depends on the specific model. Consult your user manual for precise instructions. However, a common starting position is the “choke” or “fast idle” setting. This setting enriches the fuel-air mixture, making it easier for the cold engine to start.

Once the engine catches, you can slowly move the throttle to the “run” position. This reduces the fuel-air mixture and allows the engine to run smoothly at a lower idle speed.

What happens if I start the mower with the throttle too high?

Starting a lawn mower with the throttle set too high can be detrimental to the engine. The excessive airflow and fuel mixture can cause the engine to flood, making it difficult to start or even stall completely. Additionally, the engine may run too fast, potentially causing damage to internal components.

It’s best to err on the side of caution and start with the throttle in the “choke” or “fast idle” position. You can then gradually increase the engine speed once it’s running smoothly.

What if the mower won’t start at all?

If your lawn mower won’t start despite setting the throttle correctly, there are several other factors to consider.

First, ensure there is enough fuel in the tank and that the fuel line is not clogged. Check the spark plug for proper function and replace it if necessary. Lastly, inspect the air filter for blockage and clean or replace it as needed.

Why does my lawn mower stall when I release the throttle?

The most common reason for a lawn mower stalling when you release the throttle is a faulty idle speed adjustment. The engine may be running too slow at idle, causing it to sputter and die when the throttle is reduced.

To rectify this issue, consult your user manual for instructions on adjusting the idle speed.

Should I start the mower with the choke on or off?

Starting a cold lawn mower with the choke on is generally recommended. This enriches the fuel-air mixture, making it easier for the engine to ignite and start. However, you should not keep the choke on for prolonged periods as it can lead to engine flooding.

Once the engine catches, you can gradually release the choke until the engine runs smoothly. If the engine still needs the choke after a few seconds, it might indicate a fuel or ignition problem.

What are the consequences of running the engine too fast?

Running a lawn mower engine too fast can lead to several problems, including:

  • Increased fuel consumption: The engine burns more fuel at higher speeds, leading to higher operating costs.
  • Premature wear and tear: The engine components experience more stress and wear at higher speeds, potentially shortening the lifespan of the mower.
  • Reduced blade lifespan: The blades spin faster, which can lead to premature dulling and damage.
  • Excessive noise and vibration: Running the engine at high speeds generates more noise and vibration, which can be uncomfortable and potentially harmful to your hearing.

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