Skip to content
When you find gas coming out of your lawn mower exhaust, you must take it seriously and find the reasons. It’s a common fact that your lawn mower engine might get damaged due to long use and other damages. Sometimes, our exhaust shows us the sign by emitting gas, liquid, or other fuel.
If you ask why is gas coming out of my lawn mower exhaust, you mostly get 15 reasons behind it. In most cases, I find my exhaust is broken, damaged, or clogged in different areas. It will be a crucial factor that you must solve accordingly.
15 Reasons Why Gas is Coming Out of Exhaust
After going through every aspect of a lawn mower, you will get 15 reasons gas is coming out of the exhaust. It’s time to explain them all briefly and give a clear answer. When you know the reason, you will get the solution too.
Damaged Fuel Injector
A leaking fuel injector is the first reason the gas comes out of the exhaust. It’s a common scenario to have a damaged or leaking fuel injector if we don’t change it for a couple of months. In that situation, your fuel injector will be damaged, allowing the gas to come out of the exhaust. You should clean the fuel injector regularly or replace it with a new one.
Faulty Fuel Regulator
A fuel regulator is crucial for every lawn mower since it can increase the fuel pressure without replacing your existing fuel injector. If the fuel regulator gets clogged and fails to control the fuel pressure and other jobs, it might help the gas to come out of the exhaust. Maybe your regulator is damaged or gets too much dirt.
Leaked Fuel Return Line
Another essential part of every lawn mower is the fuel return line. It works by returning the extra fuel to the pump. Your carburetor may get extra fuel that needs to be returned to the fuel pump. In that case, the fuel return line successfully does the work. If it gets damaged or it is leaked, the gas or fuel will come out of your exhaust automatically.
Burnt Valve
After rigorously using your lawn mower for a couple of months, you must have found a burnt valve in the motor. It’s not a big deal since the valve will continuously resist temperature and will be burnt after a specific time. Once it is burnt, it will start to help your fuel or gas coming out of the exhaust. You must replace this burnt valve with a new one.
Overfilled Gasoline
When we pour or add fuel to our gasoline or fuel pump, we must check the existing fuel level to ensure that the fuel pump is not overfilled. Putting too much gas or fuel into your gasoline may cause gas to come out of your exhaust. The return line or other fuel system will fail to manage the extra fuel.
Gas Burning Issues
Sometimes, the gas is not burning in your cylinder, which may cause the gas to come out of the exhaust. There are some reasons why the gas is not burning systematically. One of the key reasons is a burnt valve since it will directly help the gas to get through the cylinder and allow it to produce enough power.
Leaking Head Gasket
A leaking head gasket is another reason the gas comes out of the exhaust. In most cases, the head gasket is damaged, or it’s old enough to fail to maintain and control the gas pressure. Therefore, you will get your gas out of the exhaust, so you must change your damaged head gasket.
Clogged Air Filter
We all have air filters in our motor to filter the air and prevent any unusual particles. It works continuously to provide fresh or insignificant particles through it. Once it gets clogged or damaged after using it for a long time, the clogged air filter might indirectly help your gas come out of the exhaust.
Lack of Air
If your fuel pump is full of oil or gasoline is filled with gas, you must ensure enough fresh air to maintain the fuel system. It must have the perfect ratio of fuel/gas to air. For some reason, the air might be less than fuel or gas, forcing the unfiltered gas or fuel to come out of the exhaust. It’s another common reason your gas comes out of the exhaust.
Faulty Fuel System
Those are the specific reasons that will show you exactly why your gas is coming out of the lawn mower exhaust. Often, you will find that your entire fuel system collapses and gets damaged due to poor maintenance and other reasons. In Particular, the fuel coolant system will fail to cool down the engine. Therefore, when you stop your lawn mower engine, it will pass some fuel or gas through the exhaust.
Faulty Exhaust System
If you don’t have any of the previous problems with your lawn mower engine, you must check the exhaust system. Maybe your exhaust system is leaking or damaged due to overuse or dirt. Whatever the reason, you must repair it accordingly.
Damaged Gasoline
Although it’s not a common reason, the damaged gasoline might cause the gas to come out of your lawn mower exhaust. If the gasoline is too old or decayed, you should repair or replace it and stop the gas coming from your exhaust.
Damaged Spark Plug
The spark plugs are very crucial parts of every lawn mower engine. If it gets damaged or ruined, it will help gas to come out of your exhaust pipe.
Unburned Fuel
When you add gas to your gasoline, the fuel system will burn the gas and produce the heat or power to run the lawn mower engine. If your fuel filter is clogged or the engine fails to burn the gas, it will come out of the exhaust.
Other Reasons
After those 14 reasons, you may find other reasons why the gas is coming out of your lawn mower exhaust. Maybe your lawn mower engine is damaged and fails to utilize the unburnt fuel or gas coming through the lawn mower exhaust.
Closing Words
You get a total of 15 reasons why is gas coming out of my lawn mower exhaust. You should find the exact reason and repair or replace that part of your lawn mower engine.