lawn equipment choke symbol

Lawn Equipment Choke Symbol: How To Check Which Is On Or Off

Learning the ins and outs of your lawn mower can be filled with trials. There are so many parts and so many things to consider that it’s no wonder people find it hard to determine the symbol for choke and how to tell whether it is on or off. So how do you tell the difference between on and off with the engine choke symbol?

The choke symbol, when in its on position, restricts the airflow to the mower’s engine and you’ll know this is the case as the lever will be pointing horizontally or at a slight angle. Sometimes, these positions will be marked as choke, start, or full choke. If the choke is off then the lever will be in a vertical position and may point to the word run.

Fortunately, understanding the difference between choke on and choke off isn’t difficult to get your head around. This guide gives you all the details you’ll need to know.

When the choke symbol is on, this tells you that the level of air being mixed with the fuel in the carburetor is being adjusted. In order for combustion to occur, there needs to be a mix of gasoline and oxygen and getting the ratios just right is really important.

Your choke switch operates an internal vent and when this is open, the flow of oxygen is restricted. However, when it is closed, the air can flow freely.

The engine choke symbol tells you the current position of the choke and this has a direct impact on how the lawn mower runs. You will see the choke symbol presented as a square with a line and this is located on the throttle. The symbol lets you know whether the choke is on or off but in order to determine this, you need to know which position is which. More on that later!

When the choke is turned on, this allows for more fuel to be delivered to the engine in order to get it up and running.

What Position Is ‘Choke On’?

In order to operate your lawn mower correctly, you need to understand all of its features and that includes the full choke symbol. Near to the choke symbol, there is a lever and if this is pointing in a horizontal position or at a diagonal angle then this states that the choke is on. Note that there may be markings to tell you this such as full choke.

When the choke is in position, there is a barrier inside the lawn mower and this can prevent the carburetor from working as it normally would. When in this position, one would say that the lawn mower is ‘choked.’ The only way to get it out of this state is to pull the lever to its vertical position. When this happens, the barrier is opened and airflow is restored.

lawn mower choke on and off

What Position Is ‘Choke Off’?

If you are doing a cold start on your lawn mower engine then the choke must be accurately set to an almost closed position. However, when the choke is open, this allows more air to flow through and mix with the fuel. This improves the process of combustion and means that your lawn mower will keep running. When the choke is off, the lever will be pointing upwards in a vertical position.

How Do You Know If The Choke Is On Or Off?

It’s incredibly easy to tell whether the choke is on or off. All you need to do is locate that lever we talked about on the throttle and take a look at its position. If it is pointing upwards then this tells you that the choke is off. However, when it’s in a horizontal or diagonal position, this indicates that that choke is on.

In a lot of cases, the choke symbol will be labeled to help you better determine whether it is on or off. Note that, when on, the labels may read choke, start or full choke whereas when it is off, the label may read run.

Is It Bad To Leave The Choke On?

Whether it is a good idea to leave the choke on or not depends on several things. For example, are you leaving it on while starting the mower or are you leaving it on while running the mower? Moreover, many people want to know whether you should leave the choke on when the mower is in storage.

In all of these cases, it’s pretty straightforward as it’s always best to turn the choke off. You see, the choke is used as a way to warm up and prime the engine. Once this has happened, you no longer need to keep it on. In fact, if you do, this will probably lead to problems so just turn it off.

Can You Leave The Choke On When Starting?

The point of the choke is to make sure that combustion can happen but controlling the ratio of fuel and air within the carburetor. So, when you are starting your lawn mower up, you will need to have the choke on. When you do this, the choke helps to warm the engine and makes it easier to start.

Note that, when starting up a small engine such as the one on your lawn mower, you’ll need to use the priming bulb between five and ten times while the choke is on. After this, you can pull the cord or use the key until the engine gets going. At this point, don’t turn the choke off completely but rather reduce it to half and allow the engine to warm for a few seconds.

leave the choke on when starting

Leaving The Choke On During Operation

Once you have your lawn mower engine up and running, you will need to reduce the choke somewhat. If you leave it on full then you’re only going to end up using more fuel that is necessary so it’s hardly the most economical thing in the world.

While you could, in theory, leave the choke on, we wouldn’t recommend it if you’re going to be using the lawn mower for longer than an hour. The reason for this is that the fuel consumption would be huge but also the impact on the environment would be devastating. Plus, your lawn mower will get hotter than usual which could result in damage.

In most cases, when the lawn mower engine starts, it will start to smoke or sputter if it is left on full choke. The power won’t be as high and the mower won’t run as well as it could. However, there are times that the machine will only run with the choke on. These include when there is a fuel line blockage or a clogged air or fuel filter. Another example of this would be if you have used incorrect fuel such as one whose octane rating is not optimal.

Leaving The Choke When Storing

A lot of people will leave the choke in the on position so that they don’t have to worry about turning it on when they come to use the mower again. But this isn’t something we would recommend that you do. Why?

Well the answer is simple; the choke is designed to warm and prime your engine so there’s no need for it to be on when the machine isn’t running. Perhaps you think about leaving in a half position but that’s not advisable either. The best option; just turn it to the off position.

What Does A Choke Do?

The purpose of the choke on a gas lawn mower is to restrict airflow so that you get the right fuel and air ratio in order to get the mower up and running. When the choke is in the on position, fuel can get into the engine but when it’s left in this position, more fuel gets through meaning consumption will be much greater.

Not only does this mean that you will end up spending a lot more money on gas but the entire operation of your lawn mower could be affected. A lot of people fall into the trap of thinking that greater fuel delivery has got to be a good thing, but this isn’t necessarily the case.

In most cases, this will mean that the mower runs a lot less smoothly and if you’re really unlucky, it can result in carburetor damage. The most common issue here is related to leaking within the carb. If you don’t notice this right away then it could cause a whole world of other problems. It is for this reason that you should familiarize yourself with the choke and what it’s there for.

What’s more, if there is insufficient airflow within the carburetor then this can impact how well the engine runs. Therefore, it’s really important to pay close attention to how your lawn mower is running, whether that’s an odd sound, a strange feeling, or anything else. When you notice things, the first action you should take is to look at the choke symbol position. If it is on, turning it off could be the answer to your problem.

When starting your lawn mower with a cold engine, the choke is one of the most important components of the machine. The colder the engine when you start it, the more it requires a good blast of fuel to get it going and in these instances, the choke should always be on full.

Final Thoughts

Your petrol lawn mower is a complex piece of equipment but it’s easy to work with when you understand what each part is for.

One of the things that a lot of gas lawn mower owners struggle with is the choke symbol and determining whether the choke is in the on or off position. Fortunately, this is an easy concept to grasp. If the choke lever is facing horizontally or at an angle, then the choke is on. If it is pointing upwards, in a vertical position then the choke is off. Understanding this is important as it will help you to optimally run your machine.

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Andrew Fisher

Andrew Fisher

Andrew is a dedicated father of three who really takes pride in his lawn and garden. You'll find Andrew behind the scenes of almost everything Edge Your Lawn produces. When he's not helping readers find all the information they need, he's in his backyard working on his lawn and garden landscaping. This year he hopes to build an outdoor deck and sort out his veg patches.