Oil In Lawn Mower Carburetor – What To Do?

Were you doing maintenance on your lawnmower and found oil in the carburetor? Now, you want to know what caused it and what to do about it? You’ve come to the right place, for we have researched this question, and we have the answer for you.

There are several possible reasons how oil made its way into the carburetor of your lawnmower:

  • Tilted the lawnmower the wrong way
  • Too much oil was added
  • Oil accidentally poured into the carburetor

We have ourselves a short but complicated list there. But worry not, we will talk about each of the different causes in detail in the succeeding sections, including the possible solution to each. Read on!

Turning on the lawn mower by gardener, Oil In Lawn Mower Carburetor - What To Do?

What Happens If You Tip The Lawn Mower The Wrong Way?

The engine of your lawnmower is similar to the engine in a classic car. It has an air filter and a carburetor to get its engine going.

Unfortunately, there will be times when you need to tilt your lawnmower to access the blades at the bottom. If you tilt your lawnmower the wrong way, you’ll have a new problem after you fix one.

You need to tilt your lawnmower with the air filter and the carburetor pointing upwards. If you tilt it the wrong way, oil and fuel will flow through the cylinder and piston and make their way into the carburetor—thanks to the effect of gravity. If you tilt your lawnmower long enough, the oil can even make its way to the air filter and to the spark plug.

You will need to replace the air filter if it has oil. There is no way to clean off the oil from the air filter.

Changing The Air Filter

Lawnmower in the garden

Just like your car engine, your lawnmower needs a steady flow of air to function. The air filter is responsible for keeping dirt and particles out of the engine.

Oil on your air filter will limit the flow of air through it. If the engine doesn’t get the right amount of air that it needs, it will not be able to sustain combustion and either die out after starting or will not start at all.

Thus, it is important to replace the air filter once it has been contaminated with oil. Make sure to thoroughly clean the air filter case and dry it before putting in the new air filter. Any leftover oil in the air filter case will make it to the new air filter and contaminate it.

Cleaning The Spark Plug

The spark plug in your lawnmower is what supplies your lawnmower with the spark that it needs to maintain combustion.

Unfortunately, oil on your spark plug will prevent it from performing this function. Fortunately, it is possible to clean the spark plug. Follow these simple steps to clean your spark plug:

  1. Use pliers to hold the spark plug. This will prevent getting your hands burned.
  2. Use a blowtorch to burn off the oil deposits from your spark plug. Make sure to expose only the threaded part of the spark plug to the flames.
  3. After you burn off the oil and fuel from your spark plug, use a spray-on spark plug cleaner to get rid of the dirt and carbon deposits that remain. Leave it to dry naturally.
  4. Use 220-grit sandpaper or higher to gently clean the small metal rod sticking out of the spark plug.
  5. Clean the threads with a wire brush.
  6. Reinstall the spark plug.

Hosa D5S-6 CAIG DeoxIT Spray Contact Cleaner is available on Amazon. Check it out through this link.

Cleaning The Carburetor

Use a carburetor cleaner to remove any leftover oil that can be blocking the carburetor. Reinstall the carburetor and try to start your lawnmower.

If your lawn mower will not start, disconnect the carburetor and bring it to a repair shop. They can do a more thorough cleaning of your carburetor.

Gumout Carb and Choke Cleaner are available on Amazon. Check it out through this link.

What will happen if I pour too much oil into my lawnmower?

Parts of a petrol trimmer detail of the inlet hose that links the oil tank to the carburator. Gasoline pump for trimmer close-up

Lawnmower manufacturers recommend specific oil levels for the different models of their lawnmower. It is never a good idea to go beyond these levels—too much and too little is never good for your lawnmower.

Too much oil in your engine can cause the excess to overflow to the air filter, the sparkplug, and the carburetor. This is only the tip of the iceberg. Too much oil in your lawnmower can lead to several other problems.

How to remove excess oil from a lawnmower?

You need to get the oil level of your lawnmower down as soon as possible if there is too much oil in it. Here are the steps that you can follow to get the oil within the correct level:

  1. Remove the spark plug wire. This is to make sure that there will be no accidental spark that could light up the oil while you’re working on your lawnmower.
  2. Look for the oil drain plug or the valve port. Not all lawnmowers have one, but if your lawnmower has one, it can be found near the side of the engine close to the dipstick.
  3. If your lawnmower has a drain plug, remove it quickly and then replace it once more. This quick removal will remove oil from your lawnmower little by little.
  4. Check the oil level after you drain some of the oil. If the oil level is not yet within acceptable levels, repeat the steps that you did earlier to remove more oil. Keep repeating the steps you used until you get the oil level to within acceptable levels.

If your lawnmower doesn’t have a drain plug, you can briefly remove the oil filter and put it back once more to drain some oil.

Push mowers might not have a drain plug or an oil filter. If your lawn mower doesn’t have either one of these, you can drain the excess oil from the fill hole. You can pick any one of the methods below to remove the excess oil from your lawnmower.

  • Get a clean tube and insert it into the fill hole. Connect the opposite side of the tube to a handpump. Use the handpump to drain a little oil through the fill hole.
  • Use a long turkey baster to get some oil out from your lawnmower through the fill hole. Never use the turkey baster again for food.
  • Tilt the lawnmower a little to spill some of the oil into a container. Make sure to tilt your lawnmower the right way.

How to remove oil from the carburetor?

Detail of Guidetti Condor engine on a vintage BCS 622 lawn mower

Another reason that there is oil in the carburetor is that someone accidentally placed oil in the carburetor hole instead of the oil fill hole. This is a problem that can be solved by draining the carburetor of the oil that was placed there by mistake. Here are the simple steps that you can follow to remove the oil from the carburetor:

  1. Get a drain pan ready to catch the excess oil from the carburetor.
  2. Tilt your lawnmower with the air filter and carburetor pointing upward. Drain as much oil as you can. Alternatively, you can use a clean hose and a handpump to drain all the excess oil inside the carburetor.
  3. Push the primer 10 to 15 times. This mixes some of the fuel with the remaining oil in the carburetor. If your lawnmower doesn’t have a primer, you can remove the air filter and then spray some starter fluid into the hole where the air filter was connected before.
  4. Pull the starter cord five to ten times to mix everything inside the lawnmower engine.
  5. If the lawnmower doesn’t start, spray some starter fluid in the carburetor.
  6. Pull the starter cord once more to try and start the lawnmower.
  7. Once your lawnmower starts, the exhaust gases will be smokey. This is the oil that was added to the carburetor. Let the lawnmower run for a few minutes. This gives it time to burn the excess oil in the carburetor.
  8. Turn off your lawnmower and remove the spark plug. Check the spark plug for dirt—especially oil that could have accidentally made it to the spark plug. Follow the steps above for cleaning the sparkplug if it has oil on it.


Lawn mover on green grass in modern garden. Machine for cutting lawns.

There are a few reasons why oil gets into the carburetor of your lawnmower. It is important to clean the carburetor of oil, including the air filter and the sparkplug, before using your lawnmower normally.

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