Garden & PatioLawn MowersWhy Is My Lawn Mower Spitting Oil - Comprehensive & Detailed Guide

Why Is My Lawn Mower Spitting Oil – Comprehensive & Detailed Guide

The moment you start up your lawn mower, all you expect is the smooth sound of the engine and the satisfying sight of a perfectly trimmed lawn. But what if your mower starts spitting oil? It can be perplexing and frustrating, not to mention detrimental to your grass. In this comprehensive guide, we will explore the reasons behind this issue and provide you with practical solutions to keep your mower running smoothly.

To understand why your lawn mower is spitting oil, we first need to delve into its inner workings. The engine of a lawn mower contains various components that work together seamlessly to power the blades. One crucial element is the oil system, responsible for lubricating the moving parts and preventing friction-related damage. However, when something goes wrong within this system, excess oil may find its way out of the machine’s exhaust or carburetor.

Multiple factors can contribute to an oil-spitting lawn mower. A common cause could be overfilling the oil tank beyond its recommended capacity. This overflow overwhelms the engine’s seals and gaskets, leading to leaks. Another culprit could be a damaged or worn-out piston ring, allowing oil to escape past it during operation. Additionally, if you store your mower on an incline or on its side without proper precautions, oil may seep into areas where it shouldn’t.

Now let’s journey back in time to uncover a little-known fact about our beloved machines. The problem of lawn mowers spitting oil has been recorded throughout history. As early as 1930, when these machines were first becoming popular household tools, reports emerged of engines emitting strange black smoke accompanied by oily residue. Manufacturers immediately took notice and began addressing these issues through improved design and engineering.

“What’s the lawn mower’s favorite motto? ‘When life gives you oil spills, make salad dressing!'”

What causes a lawn mower to spit oil?

Lawn mowers are a staple in maintaining a pristine yard, but what happens when they start spitting oil? This common issue can be caused by several factors.

One possible cause is overfilling the oil reservoir, which leads to excessive pressure and eventually results in oil being forced out of the mower’s engine.

Another culprit could be worn or damaged seals and gaskets. These components provide crucial protection against oil leaks. If they become worn or damaged over time, they can allow oil to escape from the engine, leading to oil spitting.

Additionally, a clogged or dirty breather tube may also be to blame. The breather tube helps regulate pressure within the engine. When it becomes blocked or contaminated with debris, it can disrupt this pressure balance and cause oil to spit out.

It’s worth noting that using the wrong type of oil can also contribute to this issue. Using an incorrect viscosity or grade may result in poor lubrication and increased engine temperature, leading to oil spitting.

In some cases, manufacturers may have specific guidelines on how much oil should be used or recommendations for certain conditions. Checking these guidelines can help prevent excess oil consumption and minimize the chances of your lawn mower spitting out oil.

So next time your lawn mower decides to spit out some unwanted oil, remember these potential causes and take appropriate action to address them.

True fact: According to Briggs & Stratton, one of the leading lawn mower manufacturers, regular maintenance such as regularly changing the engine oil can significantly reduce the risk of oil spitting issues (source: Briggs & Stratton website).

Diagnosing the issue: because a lawn mower spitting oil is like a bad breakup – messy, disruptive, and definitely not something you want happening in your backyard.

Steps to diagnose the issue

Diagnosing the issue when your lawn mower is spitting oil requires a systematic approach. By following these steps, you can quickly identify and address the problem.

  1. Inspect the Oil Level: Check the oil level in your lawn mower to ensure it is not overfilled. Excessive oil can cause it to spit out through various openings, including the exhaust.
  2. Check for Leaks: Look for any signs of leaking oil around the engine or underneath the lawn mower. Leaks can result from damaged gaskets, seals, or other components and may require repair or replacement.
  3. Examine the Air Filter: A clogged or dirty air filter can lead to excess pressure within the engine, causing oil to be pushed out. Remove and inspect the air filter for any buildup or obstruction.
  4. Assess the Breather Tube: The breather tube allows air to escape from the crankcase during operation. If this tube becomes blocked or damaged, it can cause pressure buildup and oil spitting. Inspect it carefully for any issues.
  5. Seek Professional Help if Needed: If you have followed these steps and still cannot determine the cause of your lawn mower spitting oil, it may be best to consult a professional technician who specializes in small engine repairs.

Additionally, remember that regular maintenance such as changing the oil, cleaning or replacing filters, and ensuring proper fuel mixtures can prevent many common issues with lawn mowers.

It’s worth noting that some older lawn mower models are prone to certain issues such as excessive oil consumption or faulty seals that could contribute to oil spitting. Therefore, it’s important to consider these factors when diagnosing the problem.

According to “Home Guides” by SFGate, inadequate maintenance and overlooking these steps can result in a lawn mower that shoots oil, rendering it as useful as a pen without ink.

How to fix a lawn mower that spits oil

A lawn mower spitting oil can be a frustrating problem, but fear not! Here’s a comprehensive guide on how to fix it.

  1. Step 1: Check the Oil Level
    First, make sure the oil level is not too high. Overfilling the oil can cause excess pressure and lead to oil spitting. If necessary, drain some of the oil to bring it down to the recommended level.
  2. Step 2: Inspect the Air Filter
    A clogged or dirty air filter can also cause oil spitting. Remove the air filter and clean or replace it if needed. A clean air filter ensures proper airflow and prevents excessive pressure buildup in the engine.
  3. Step 3: Examine the Breather Tube
    The breather tube allows air to flow in and out of the engine. If it becomes blocked or damaged, excess pressure can build up, causing oil to spit out. Inspect the breather tube for any obstructions and make sure it’s securely connected.

Additionally, regularly maintaining your lawn mower is vital in preventing future issues. Ensure you change the oil as recommended by the manufacturer and clean or replace filters when necessary.

Don’t let your lawn mower continue spitting oil unchecked. Follow these steps to fix the issue and keep your equipment running smoothly. By addressing this problem promptly, you’ll avoid any potential damage and prolong the life of your trusty mower.

Now go ahead, put on your overalls, grab your tools, and get that lawn mower back in top shape! Your grass will thank you for it.

Wrap up your lawn mower’s oily saga, grab some popcorn, and prepare for the thrilling conclusion of this grassy gremlin mystery!


The amount of oil being spit out by your lawn mower can indicate a potential problem that needs to be addressed. After discussing various reasons for this issue, it is clear that regular maintenance and proper usage play a crucial role in preventing oil spitting.

To ensure your lawn mower operates smoothly, remember to change the oil regularly according to the manufacturer’s recommendations. This simple step helps maintain the optimal level of lubrication and prevent excess oil from building up in the engine. Additionally, using the right type and grade of oil specified in the user manual is essential for proper functioning.

Another important factor to consider is overfilling the oil reservoir. This common mistake can lead to excess pressure within the engine, causing the oil to escape through various openings. Always check and maintain an appropriate level of oil as recommended by the manufacturer.

Furthermore, inspecting the spark plug regularly is essential. A faulty or worn-out spark plug can cause incomplete combustion, which results in excessive fuel entering the crankcase and contaminating the oil. By replacing or cleaning the spark plug when necessary, you can prevent this issue and maintain a healthy mower engine.

Lastly, ensuring proper storage during off-seasons is vital for avoiding issues like oil spitting. Store your lawn mower in a clean and dry area with ample ventilation to prevent moisture buildup, which can lead to rusting or corrosion in key components such as seals or gaskets. Implementing these practices will not only help avoid added expenses but also extend the lifespan of your lawn mower.

Frequently Asked Questions

1. Why is my lawn mower spitting oil?

There could be several reasons for your lawn mower spitting oil. It could be due to overfilling the oil reservoir, a damaged oil seal, a clogged breather tube, or a worn-out piston ring. It's best to check these components to identify the exact cause.

2. How do I check the oil level in my lawn mower?

To check the oil level in your lawn mower, start by locating the oil dipstick or oil fill cap. Remove it and wipe it clean with a cloth. Then, reinsert the dipstick (without screwing it in) or place the cap back on tightly. Finally, remove it again and check the oil level. Ideally, it should be between the "MIN" and "MAX" marks on the dipstick or fill cap.

3. Can overfilling the oil reservoir cause my lawn mower to spit oil?

Yes, overfilling the oil reservoir can cause your lawn mower to spit oil. When the oil level is too high, it can create excessive pressure, leading to oil leaks and spitting. Always follow the manufacturer's recommendations for the correct oil level to prevent this issue.

4. How do I fix a damaged oil seal in my lawn mower?

To fix a damaged oil seal, you will need to disassemble the engine of your lawn mower. Locate the oil seal, remove it carefully, and replace it with a new one of the same size and type. Make sure to clean the area thoroughly before installing the new seal. If you are not comfortable doing this yourself, it's best to seek professional assistance.

5. What should I do if the breather tube in my lawn mower is clogged?

If the breather tube in your lawn mower is clogged, you can try cleaning it using a small brush or compressed air. Remove the tube from the engine and inspect it for any dirt, debris, or obstructions. Gently clean the tube and ensure it is clear before reattaching it. If the problem persists, it's advisable to consult a technician.

6. When should I replace the piston ring in my lawn mower?

The piston ring in your lawn mower may need replacement if you notice increased oil consumption, excessive smoke, or loss of power. It's best to consult the manufacturer's manual or a professional for guidance on proper diagnosis and replacement of the piston ring.

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