Electric Lawn Mower Smoking: Reasons & Solutions

Electric lawn mowers emitting smoke is never a good sign and is something to be concerned about. You can try to fix the problem yourself or you might need to seek out professional help. 

Smoke emitted from a lawn mower can be of different colors, and it may be the result of several issues. We will be discussing the main reasons your electric lawn mower is smoking, and will provide a step-by-step guide of how to fix these issues.

So, without further delay, let’s begin. 

Common Reasons Of A Smoking Lawn Mower

It can be disturbing to see smoke coming out of a lawn mower every time it’s used. In some cases, the issue is minor and it could go away after a few days. But if it doesn’t solve itself, then it is necessary to fix the issue or take it to a  professional. 

There can be several common causes for the lawn mower emitting smoke. The most common cases are:

1. A worn out engine 

A worn out engine due to lack of use over long periods of time. This can actually cause several issues, one of which being emitting black smoke while running.

2. A cracked crankcase(a metal that encloses the whole crankshaft) and oil spilled on the engine

A leaking or cracked crankcase may lead to oil spilling onto the engine, this spilled oil will then burn and produce white/blue smoke. 

3. Loose or broken filter cap 

This is one of the main reasons for spilling fuel and producing oil on the engine. And it will definitely burn the fuel/oil which then creates the smoke. 

4. A faulty lubrication system 

A faulty lubrication system will result in oil, dust and dirt entering the system and gradually destroying the engine. 

5. Overfilling the oil/gas tank 

If you overfill the fuel tank, the oil will start to leak due to friction and the engine will start to burn the extra oil.

6. Damaged head gasket 

Basically, a head gasket is used to seal the internal combustion gasses within the cylinder. And helps to prevent fuel leaking into the cylinder. A damaged head gasket may produce a lot of smoke and it won’t disappear quickly. It needs to be repaired as soon as possible.  

Different Types Of Smoke And Fixing Them

There are different types and colors of smoke to look for. Basically, the color of the smoke is primal information and can help to solve the issue quickly.

So, firstly you  need to identify which color of smoke it is and then fix the issue accordingly. Here we will outline the two main types of smoke you’ll encounter: white or blue smoke, and black smoke.

White Or Blue Smoke

Emitting white or blue smoke basically means your mower’s engine is burning off the excess oil. There is also a possibility that oil has spilled on the engine parts. 

White or blue smoke can arise from any of the following 3 reasons:  

1. Overfilling the mower’s engine with oil 

When the mower’s engine is filled with too much oil, it starts to leak due to a high amount of friction. The excess oil in the tank may drown in the crankcase of the engine, which leads to emitting white smoke burning the oil.

Fixing the overfilling issue 

• Using the dipstick, determine the current level of the oil in the reservoir tank. 
• If the level of oil is higher than the given scale, drain the excess oil from the tank. It’s important to prevent oil from scattering into other components while draining the oil. If any excess oil is spilled anywhere, clean up the oil carefully. 
• Lastly, replace the oil filter and re-check whether the oil is filled appropriately up to the marked level. 

2. Oil spilled on the engine 

Another common source of white smoke is the oil spilled onto the engine’s body, which will then burn oil when the engine heats up.  

Fixing the oil spilled on the engine 

• Start the engine of the mower and let it burn the extra spilled oil. 
• Wait till the engine burns off the excess oil and the smoke disappears completely. If the smoke doesn’t dissipate within 15-20 minutes, there is a possibility of having a bigger issue. Seek help from any profession to solve the issue. 

3. Leaked gasket 

Faulty or damaged gaskets can produce a lot of smoke and can be a major issue if you don’t resolve it immediately. If the mower has a leaked head gasket, then smoke won’t disappear easily. In fact, the smoke produced from the leaking gasket leads to low power gain(low ratio of output to input power) from the engine. 

Replacing the damaged gasket 

• If you have an OHV(Overhead Valve) engine, only then you would find the head gasket in it. Take off the spark plug wire and remove the cylinder head bolts from the engine block. 
• Take out the leaked gasket and replace it with a new one. Place the new gasket on the engine block and place the cylinder head back into its position. Lastly, reinstall the plug wire on the spark plug. 

Black smoke 

In most of the cases, black smoke is produced due to the high mixture of air and fuel. Besides, insufficient air, incomplete combustion, and dirty carburetor are the causes of black smoke. 

There are 2 main sources of black smoke, including: 

1. Clogged air filter 

Due to dirty or blocked air filters, sufficient air can’t pass into the carburetor. Air flow is restricted due to blocked air filters and as a result the combustion mix doesn’t contain enough oxygen in it. 

Fixing a clogged air filter 

• You can use an aerosol cleaner to remove a small amount of dirt from the filter. 
• But if the filter is severely blocked and needs a deep clean, just take it out and wash it with dish soap and lukewarm water. 

2. Faulty carburetor 

Another source of black smoke is the wrong adjustment of fuel mixture that enters the carburetor. 

Cleaning the carburetor 

• Loosen the screw using a plug wrench and remove the bowl from the lawn mower. 
• Use a carburetor cleaner to clean the dirt and residue from the screws and bowl. Also, use a brush to clean the holes underneath the carburetor. 

Conclusion 

The causes mentioned above are the most common sources of emitting smoke from the lawn mower. However, if you find that the previous solutions aren’t helping to reduce the smoke, then there might be a severe issue with your lawn mower. 

No need to worry here. Simply consult with a professional to  have it repaired. If the mower is still under warranty, take it to the nearest service center as soon as you can.