Why is oil coming out of the lawnmower’s exhaust?

Approx Reading Time: 8 minutes

You are busy mowing your lawn with a lawnmower. While working, all of a sudden, you notice that oil is coming out of your lawnmower’s exhaust, and you get frustrated as you should be. This can be a severe issue, and if it is not fixed on time, it will cause some more damage to your mower’s engine as well. If you notice the oil is coming out of your lawnmower exhaust, you should stop mowing and check it at once. Otherwise, the oil will leak all over the yard. This is a severe issue, but it can be solved quite easily. In this article, we will help you in solving this issue. Oil coming out of the exhaust indicates some damaged parts of your lawnmower or some technical faults. This needs to be fixed, as well. It happens because of some internal engine problems or technical defects and needs a quick repair. Lack of maintenance will not allow your lawnmower to work correctly, and you will face similar issues.

If you face leakage issues, you may get frustrated, but this article will tell you how to solve these common issues. The common causes of oil coming out of the lawnmower’s exhaust are mentioned here. There can be a problem with your engine or maybe some technical faults. If the parts of your lawnmower are damaged or worn out, then you need to replace them immediately. We will tell you some simple techniques that will allow you to fix your problem correctly by yourself.

What to do if the oil is coming out of the lawnmower exhaust?

  • Step 1: Check the lawnmower level.
  • Step 2: Remove the excess oil.
  • Step 3: Check the filter.
  • Step 4: Adjust the carburetor.
  • Step 5: Check the muffler.
  • Step 6: Check the worn-out valves.
  • Step 7: Check the internal components.
  • Step 8: Check the quality of the oil.

By following the above solutions, you can fix the issue yourself. However, if you need a repair, you should call a professional if you don’t know what to do.

Steps to follow:

The oil can come out of the lawnmower exhaust due to some reasons. It can be any technical fault or some other issue. Some of the problems are very simple, and some are very serious and very harmful as well. These severe issues also require some complicated repairs. Following are some coming step that needs to be followed if oil comes out of the lawnmower’s exhaust.

Step 1: Don’t tilt the lawnmower greater than 15 degrees

If you tilt your lawnmower greater than fifty degrees, the oil may leak from the crankcase and move toward the carburetor. This may cause the oil to come out of the exhaust. It mostly happens when you are riding on a hill, the lawnmower is tilted, and the oil will flow towards the carburetor and then out of the exhaust.

Step 2: Squeeze the excess oil from the foam air filter

On the other hand, overfilling is the other cause that can allow the oil to come out of the exhaust. The lawnmower’s crankcase is very small if it needs less than 1 quart of oil to be filled. If it is overfilled, the oil can move anywhere. It can move towards the air filter, carburetor, or maybe towards the cylinder. So, if the crankcase is crammed, the overfilled oil can come out of the exhaust. This oil should be added very little at a time.

Step 3: Repair or replace the Clogged Air Filter

If the air filter is clogged, some of the fuel has remained unburnt. It will not allow the air to pass through the piston, due to which some of the power will remain unproduced. The air filter consists of a foamy structure that blocks any impurities like dirt, debris, and insects. If it has become porous or faulty, an adequate amount of air doesn’t pass through. This is the actual reason behind improper fuel combustion. You need to clean the filter to solve the issue. Otherwise, the unburnt fuel will cause the oil to leak too along with the fuel residuals.

Step 4: Adjust the Carburetor

The carburetor is an essential part of the lawnmower. If it is not working correctly, the carburetor will also face issues. You should keep your carburetor adjusted because if the carburetor is not changed, the fuel fails to burn. This unburnt fuel will come out of the exhaust. The carburetor needs to be adjusted to solve this issue.

Step 5: Check the Muffler

The fluid coming out of the muffler is most commonly the unburnt fuel. If the carburetor is unadjusted, the power remains unburnt. On the other hand, if the air filter is clogged, the energy will remain unburnt. This unburnt fuel ejects out of the exhaust system. If the liquid coming out of the muffler smells like gas, then this problem is known as flooding. The muffler needs to repair or replaced to stop flooding.

Step 6: Replace the worn valves

 Valves are used in the cylinder of the lawnmowers to seal them properly to avoid any leakage. If these valves are worn out, then the cylinder will not be adequately filled. As a result, the oil will leak from the cylinder and will come out through the exhaust. Therefore, replace the worn valves.

Step 7: Fixing Internal Problems

There can be some internal problems of the engine due to which the oil leaks from the exhaust. Some of them may include:

  • Blown head gaskets: The head of the engines are blocked by the head gaskets. If these are not appropriately secured, the oil may move to the exhaust. If these gaskets are damaged, the oil will move towards the exhaust and then come out of the seal.
  • Cracked Engine Block: Cracking of the engine blocks causes leakage. If the engine blocks are cracked, the oil will leak from them.

Step 8: Check if the oil is bad

The oil that comes out of the engine and then from the exhaust may cause some issues. Following are some:

  1. White smoke: The oil coming out of the engine interacts with the other components and then produces white smoke. This smoke can be hazardous for the environment and your lungs as well. In this case, the oil needs to the replaced, and the filter needs to be cleaned.
  2. Dead Grass: The oil that leaks soak into the grass. The soil is damaged, and it will produce dead grass. This will be very rough and will not look beautiful. Make sure to replace the oil timely and clean the grass filter too.

Frequently asked questions:

1. How to prevent oil from leaking into the engine?

If you want your lawnmower to work correctly for a more extended period, you need to maintain it properly. Proper maintenance allows the lawnmower to work appropriately for a more extended period.

2. Should I take a lawnmower to the shop if I notice oil in the exhaust?

Oil in the exhaust can be due to faulty filters, low quality of fluids, or rough operating conditions. If you don’t know how to fix the issues, you may call a professional.

3. What causes the gas to come out of the exhaust?

This is due to the excess fuel. On the other hand, a leaking fuel injector may also be the reason for this. The unburnt energy comes out of the exhaust.

4. How to check the oil level of the lawnmower?

The dipstick should check the oil level. Firstly you should remove and clean it with a cloth. Secondly, place the dipstick back into the mower. Now check where the oil comes up to. If it reaches a top, then it is filled. But if it is more than that, then it may cause some issues.

Final Remarks

The lawnmower needs proper maintenance to work correctly. On the other hand, if it is not maintained correctly, you may face the issues mentioned above. It is quite frustrating, too, and can be costly sometimes. The above mentioned are the causes and solutions of why oil comes out of the exhaust. If you face the same issue, you need to go through the causes and solutions properly. We have explained an easy fix to your problem that you can do yourself. However, if you are confused about what to do, you should take your lawnmower to a repair shop or call a professional. Don’t try to do it yourself if you don’t know exactly what to do. It would help if you also took care of the safety precautions while repairing anything. If your lawnmower faces the above issues, follow the steps given above. This will help you fix your problem by yourself quite quickly. If you want to make your lawn look more beautiful, you need the right lawnmower that works properly. So, it would be best if you took great care of lawnmowers and their maintenance. This will allow your lawnmower to run correctly for a more extended period.