How to Change Oil in Lawn Mower? – 7 Simple Steps

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Just like cars, motorcycles, and power saws – lawn mowers also need their oil changed from time to time. 

Because their engines produce a lot of soot and the oil gets dirty and burned over time – you’ll have to replace the lawn mower oil consistently.

It is essential for the engine if you want to prevent damage and keep it working smoothly. Otherwise, you may end up with severe problems that may not let you mow your lawn anymore.

How to prevent that? You just need to learn how to change oil in a lawnmower. Here, we’ll teach you everything you need to know about that. 

Why Change Oil on a Lawn Mower?

To change oil from your lawnmower may seem like a useless endeavor at first. But it’s not – just like any other machine with an ignition engine, lawnmowers need their oil changed. 

Want to know why? Here are a few reasons: 

Cleans Engine Interior

The first and most important reason to change the oil from your mower is cleanliness.

There’s probably nothing worse than an engine with dirty oil. When the oil is too dirty, it turns into sludge. It reduces the efficiency of the pistons, clogs its tubes and crevices, and sometimes reduces performance exponentially. 

With clean oil, you can prevent all that. 

Lubricates & Cools Down

The valves, pistons, tubes, and other parts of an engine need constant lubrication. With so many moving pieces, it is crucial to ensure proper movement and smoothness inside. This way, the engine produces the least amount of friction and works at its max. 

Similarly, the friction from the moving parts can create a lot of heat. If the temperature goes too high, the pieces will start to burn and wear off – possibly causing permanent damage. In some cases where oil is not changed correctly, the engine stops working completely. 

What to do to prevent this? Easy – you replace the old dirty oil that creates friction with the new one. 

change oil in lawn mower

Increases Mower Lifespan

The wear that internal parts of an engine get when the oil is too dirty won’t necessarily damage the engine at once. It could also start to wear the engine slowly, causing damage to some of its parts and reducing its lifespan.

So it is not only essential to do oil change consistently, but also as soon as necessary. Otherwise, the damage will still happen. And it can wear down the engine exponentially. 

Makes it More Efficient

Once the engine wears down from using dirty oil, it won’t only start having issues related to performance – it will also begin to burn more gas for less potency.

In the short and long term, this decreases the mower efficiency exponentially. You’ll feel like the tank empties faster. 

So, want to get the most out of every gas refill? Then be sure to change its oil consistently. 

lawn mower oil

How Often Should I Change Lawn Mower Oil?

You should change the oil of your lawn mower every time it reaches 50 hours of operation. In some cases, you may need to replace it with even less use than that.

If you check oil level, and it is too little – there’s probably a leak or the oil is evaporating. But if it is too dark, it probably means the engine is producing too much soot. Either case, you need to change it. 

And finally, you may need to change the oil depending on the season. Some oils work well in hot seasons. But the same oil won’t do a proper job in cold environments, so you may need to change it for new cold-season oil.  

Now that you’re aware of the benefits and how often you should change the oil in your lawnmower, let’s see how it’s done. Follow these steps:

1. Gather the Tools & Proper Oil

While the process may seem like you can get the job done without tools, it is not possible.

At the same time, you need to pick the ideal oil if you want to lubricate the engine correctly.

In this step, you’ll learn what tools you need, and what oil you should go for. 

Read the Manual

Before you gather any tool and pick any oil, read the instruction manual of your mower. If it is too old and doesn’t have any, then you can skip this.

Typically, the owner’s manual tells you everything you need for the oil change. From the tools to the ideal type of oil, and much more – so you can get it done with little effort.

If the manual is good enough, it will tell you everything. Then, you can proceed with the process. 

Gather the Tools

how to change oil in mower

If the mower’s manual doesn’t tell you much or if the machine is too old – then we recommend using these tools:

  • Socket wrench 
  • Socket wrench extension (Optional)
  • Wrench spanner (Optional)
  • Spark plug wrench
  • Pan or bowl
  • Disposable gloves
  • Large pieces of newspaper, trash bag(s), plastic sheeting or rags
  • A piece of clean cloth

This will be enough to get the job done without making a mess. Below, we’ll tell you how to use them. 

Find the Right Oil

Once you have the tools, then you need to find the ideal oil. If the manual doesn’t tell you what kind to go for, then our in-depth article about this will help you out. 

It is essential to use the right oil, or you may end up clogging the engine or gumming the piston. Both will make the engine less efficient and probably even damaging it forever. 

2. Find a Proper Place

When it comes to working with lawnmowers, we recommend a place where a little bit of oil on the floor won’t cause any damage.

Places like a garage, outdoor porch, a concrete patio, or even a driveway can be excellent choices. 

Prepare the Area

Once you have an ideal place to work with your lawnmower, then you can proceed to prepare it.

What does this preparation mean? Well, you just want to prevent making a mess on the floor. Even in concrete or even ceramics, oil tends to be challenging to clean.

To prepare the area, you should place newspapers, plastic sheeting, or rags covering the floor. A trash bag may also do the job. This will prevent any spilled oil from reaching the floor. 

3. Prepare the Engine

By now, you should have the right place figured out. It’s time to prepare the engine for the oil change. Put the gloves on and proceed: 

Warm It Up

You should proceed by warming up the engine. For that, start the mower. We have a comprehensive guide on how to do that.

If you know how to start it without help, then do so. Leave the engine running for about 5-10 minutes.

Warming up the oil will make it lighter and smoother. That will make it easier to get the oil out of the engine. 

After 5-10 minutes, when the engine feels hot enough, you can turn it off and proceed. 

Disconnect the Spark Plug

changing oil in lawn mower

Then, you need to get the spark plug wrench and get the spark plug out.

First, however, disconnect the spark plug wire so you can have free access to the plug itself.

This will prevent the machine from starting while you’re emptying it or filling it. 

Read more: What Spark Plug to Use on a Lawn Mower?

Empty the Gas Tank (A Little)

You won’t need to empty the gas tank completely. But it is safer if you get rid of at least 90% of the gas.

This process is not difficult, either. You can follow our guide on How to Drain Gas Tank from Lawn Mower for a better idea of how to do it.

Be sure to leave some gas behind so you can start the mower after finishing the whole process. 

Clean the Fill Area

Here, you need to check oil level and see whether it is lighter. If it is, then you’re ready to drain it.

But first, clean the fill area. This is a small plug-like cap where you pour the oil. Use the damp cloth to lightly get rid of any dirt. 

4. Drain the Oil

Draining the oil requires you to follow a few steps to do it right. Otherwise, you may either leave some oil inside or make a total mess.

Place the Pan 

changing oil in lawn mower

Start by putting the pan/bowl over of the plastic sheet, trash bag, rag, or newspaper. If it is a flat portion of the floor, that’s even better. You can prevent any spill this way.

This is where you’re going to drain the oil from the mower. So try to secure it as well. You can place rocks on the sides or inside so you can prevent it from moving or tipping in the process. 

Open the Drain Cap

Now that you have the jug/bowl in the ideal place, then you need to get the drain cap off the mower.

This piece usually comes with a socket head of 3/8-inch. So you’ll need a socket wrench of this size. 

Be aware that in some mowers, the drain cap is located deep inside into the body. In that case, you will have to use an extension to reach the cap and loosen it up.

In some cases, you may not need the socket wrench at all. This happens when the drain cap comes with a handle or two prongs you can turn and loosen.

Be sure to remove the drain cap so you can proceed to drain the mower out of oil. 

Tip the Lawn Mower

lawn mower maintenanace

To drain the oil, you should tip it to the side. The lawnmower should start dripping oil directly from where the drain cap is.

Be sure it starts dripping oil directly into the jug or bowl below. Leave it in this tilted position for at least one minute so all the oil can drop out of the engine.

5. Replace the Oil Filter (If Necessary)

Some lawn mowers come with an oil filter. Once you’ve drained the engine, we recommend replacing this filter.

It is like a carburetor, but for oil. And it should be replaced along with the oil. Here’s how:

Unscrew the Filter

Most oil filters come right out by unscrewing it by hand. Some of them may come out only with a socket wrench or spanner. 

Use the right tool as needed.

Catch the Oil

The filter will probably drip some oil (even after draining the engine), so be sure to have the container with the dirty oil close.

Let it drop oil for a few seconds before throwing it in the trash or cleaning it (if you don’t have a replacement).

Coat the New Filter Seal

If you’re installing a new filter, then we recommend oiling the area where the old filter was with the new oil. 

This coating will prevent the filter from sealing improperly or getting stuck later on. No need to use too much oil, though. A few drops in a cloth and a light swipe on the area should suffice. 

Install the New Filter

Now you can install the new filter. Be sure it is what the mower uses. 

Turn it clockwise until it tightens up in place. If it feels like it doesn’t fit properly, you may need to swipe a little more oil in the area, so it fits smoothly and seals well. 

6. Fill With New Oil

Is the lawnmower drained out of oil and with the new filter installed? Then you can proceed to fill it up with the new oil.

Here, you’ll have to do it properly. Remember to follow the owner’s manual as to how much oil you need to add, what type, and how to pour it inside.

Pour Oil Gradually

how to change oil in lawn mower

To change oil, you need to pour a new one inside. This won’t be easy, so we recommend using a funnel if possible.

The oil goes directly into the drain cap. Be sure to have the dipstick to check the level close.

As you pour, calculate the right amount. You don’t want to overfill or underfill. Use the dipstick to measure once you think you’ve poured enough.

If it is too much, then drain some of it back into the container. Otherwise, keep adding.

In case the oil in the dipstick matches the “full” line, then you can stop pouring. 

Let it Settle

After pouring the oil inside the engine, you should leave it to settle for at least 5 minutes.

This will help the oil reach every place in the engine and cool down a little.

After a few minutes, you should recheck the oil level and see whether it says full. It should be close to the same level as before. 

Place the Cap

Once you’ve poured the oil and let it settle, then you can proceed to place the cap back into the drain/filling hole.

Be sure to tighten it up properly. You should do this with the socket wrench again. In case it is by hand, then be sure it fits tightly.

After putting the cap, you’ve successfully changed your oil. 

7. Clean & Test

Don’t rush out to use it right away, though. We recommend testing and cleaning everything before finishing.

Clean the Area

Remember that working with oil is messy. Don’t leave the area until you’ve successfully cleaned any mess you’ve made.

Get rid of the newspaper, trash bag, plastic sheeting, or rags you placed on the floor. Wipe with detergent if needed.

Go and grab the oil container and seal it up with its cap. Store it in a dry and cool place.

Finish by disposing of the dirty oil as needed. You may want to set it aside to recycle if possible. 

Reconnect the Spark Plug

Now re-attach the spark plug using the proper wrench. You may need to get your hands dirty once again. 

Be sure the spark plug is tightened correctly and reaches the ignition chamber. If it doesn’t, then it won’t turn on. Fix as needed. 

Test the Mower

Be sure to be in a place with grass, so you don’t cause any damage to floors. Now, you can start the lawnmower and test it. 

Search for any weird sound, any sign of smoke, or overheating. Let it run for 5 minutes without moving it.

If it doesn’t have anything strange to worry about, then you can use it. You’ve successfully changed the oil from the lawnmower.

Change your Lawn Mower Oil Now!

So, do you have any doubts about how to change the oil from a lawnmower? We hope you don’t. That means you’re ready to get the job done.

Replacing old lawn mower oil for a new one is essential for the mower’s longevity. And as such, you should do it consistently.

Follow this guide, and you won’t have any trouble doing so. Also, check the following related aricles.

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