Reasons Your Bad Boy Lawn Mower is Smoking

You’re sitting in a cloud of smoke. Your Bad Boy lawn mower is emitting so much smoke that it’s very alarming. The first thing that comes to mind is the money it’s going to take to repair your mower’s problem.

While smoking can signify an engine problem, it could also be a problem that can easily be repaired when caught early without a significant expense.

A Bad Boy lawn mower begins to smoke when the air filter is plugged; the engine oil level is insufficient; an engine gasket failed, or there is internal engine damage including piston ring or valve train problems. Smoking may also occur when oil is spilled or begins leaking on the engine or muffler.

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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.

Reasons Your Bad Boy Mower is Smoking

Clogged Air Filter

Never run your Bad Boy mower without an air filter. The air filter is the first line of defense to keep dirt and debris from getting into your engine. If they do get into the engine, there can be damage to the piston, seals, internal parts, and cylinder.

The air filter must be kept clean. I recommend starting each mowing season with a new air filter and cleaning it several times throughout the season. You must clean and replace it more frequently if you are mowing in dry dusty conditions.

When the air filter becomes plugged with dirt and debris because it isn’t kept clean, your Bad Boy mower isn’t able to get the air it needs. This can result in smoke emitting from the mower because of one of these reasons:

• The engine’s inability to get good air will cause your engine to run rich so black smoke will emit from your mower. This means the fuel and air mixture the engine requires to run has a higher concentration of fuel.
  
• Smoke can be a result of your air filter becoming so plugged, it restricts all air to the engine. The engine will begin drawing air from wherever it can find it including the engine crankcase. When it draws air from the crankcase, it can also pull oil from the crankcase that burns off in the cylinder.
  
• When your Bad Boy mower begins to smoke, the air filter can become plugged with smoke making your engine problem worse.

Follow these cleaning instructions for your type of air filter:

Clean a Bad Boy paper air filter element

• Remove the filter from the air filter housing.
• Wipe out any dirt remaining in the housing and don’t allow any of it to fall into the air intake.
• Tap your filter against a solid surface to get as much dirt to become loose and fall out of the filter as possible.
• Hold your filter up to a light source. Reuse your filter if you can still see light shine through the paper. If you can’t, it’s time to buy a new filter and install it.
• Reinstall the air filter and attach the air filter cover.

Clean a Bad Boy foam air filter element

• Remove the filter from the air filter housing.
• Wipe out any dirt remaining in the housing with a clean dry cloth. Do not let any dirt fall into the air intake.
• Inspect your foam filter. If it has brown areas, tears, or appears dry and brittle, do not reuse the filter. Instead, replace it with a new air filter.
• If your filter looks to be in good condition, clean your filter with mild dish soap and water to remove dirt and any oil on the filter.
• Rinse the filter until the water runs clear and all soap has been removed.
• Lay flat to air dry. Leaving outside on a sunny or breezy day will speed up the drying process.
• Once dry, lightly saturate the filter with foam filter oil. You do not want it dripping with oil. If you have too much oil on the filter, you can squeeze out the excess oil or use a paper towel to absorb it. If you purchased a new air filter, add filter oil to it.
• Reinstall the air filter and attach the filter housing cover.

Insufficient Engine Oil Level

Not only is it important to make sure you have enough engine oil in your Bad Boy mower, but it is also important to not overfill your lawn mower with engine oil. Either of these insufficient oil levels can have negative effects on your engine and cause it to smoke.

Engine Oil Level is Too Low

Oil is needed to keep internal engine components lubricated so they are able to move freely. When the crankcase doesn’t have enough engine oil, the moving parts create friction. This friction builds heat.

The engine can get so hot the oil can begin to burn and the engine parts can begin to melt causing your Bad Boy to smoke.

Smoke coming from a mower due to low engine oil is not a good situation. You can attempt to add fresh oil to bring the oil up to the correct level, but usually, when the mower smokes because of low oil it isn’t going to be this easy of a fix.

Most likely, your engine has been permanently damaged and must be repaired. I suggest taking your lawn mower to an experienced small engine mechanic to be diagnosed.

The mechanic has special engine tools to test and isolate the problem. Before spending money on repairing the engine, it is a good idea to get a repair quote and compare it to an engine replacement.

Depending on the amount of damage and age of the machine, you may choose to invest in a new engine or mower.

Because of the damage that can be caused by running a low level of oil, it is important to take a few minutes before each mowing to check your mower over including checking the engine oil level. It’s best to catch this problem early and avoid running your mower in this condition.

Engine Oil Level is Too High

You are aware that you shouldn’t run your engine when it is low on oil, but did you know running it with too much oil will also cause problems?

Many people don’t realize too much oil increases the pressure in the crankcase. This can push oil into the cylinder and even into the air intake through the valve train.

The oil in the cylinder will begin to burn off and create smoke. You can read more about additional problems you may experience when running too much oil in your Bad Boy mower in this article.

When you find too much oil in your crankcase, correct the engine oil level by removing a little oil. You can do this by removing a little oil through the drain plug or oil filter. You can also use an oil evacuator or turkey baster to suck a little oil out of the oil fill area.

Recheck your engine oil level using the dipstick once you have removed some oil. Continue to add or remove oil until the level is corrected. Check your air filter to make sure it is not covered in oil or has become plugged from smoke. If it is, install a new air filter.

Bad Engine Gasket

Smoke coming from your Bad Boy could be the result of a bad gasket on your mower causing engine oil to leak. When oil is leaked onto a hot surface, like your muffler, it will begin to burn off and smoke.

Internal Engine Damage

The smoke coming from your Bad Boy mower may be the result of internal engine problems.

Once you have reached this section, it becomes increasingly difficult to identify the exact cause of your internal problem without tearing down your engine and performing leak-down and compression checks.

You can perform one simple check that will signify you have an internal engine problem, but it won’t tell you the exact problem. You’ll need a small engine mechanic to diagnose your engine to find the root cause.

While this check can’t tell you what kind of problem you have, you’ll know you have a problem that needs to be addressed by a mechanic.

To complete this check, remove your spark plug(s) and check for signs of oil on the plug. Oil on the spark plug will indicate you may have a piston ring or valve train problem.

Piston Ring Problem

Your engine will need to be torn down to find a problem with your piston ring. When a piston ring or scoring inside the cylinder wall is found, oil can enter the combustion chamber and burn off causing your Bad Boy mower to start smoking.

Valve Train Problem

A Bad Boy mower that has overheated can develop a burnt valve. The only way to determine a burn valve problem is by removing the cylinder head and performing a leak-down test.

This test and repair should be performed by a small engine mechanic. The mechanic will have to cut the seat and the valve correctly to properly complete the combustion chamber.

Your Bad Boy Mower is Blowing Blue, White or Black Smoke: What’s the Difference?

I always recommend going through the steps above to identify the cause of the smoke coming from your mower. However, identifying the color of the smoke can point you in the direction of the potential cause of the smoke.

Blue or White Smoke

Blue or white smoke is associated with the burning of excess oil. This could be from oil burning off in the combustion chamber from damaged piston rings, valve train, or engine gasket leaks.

It can also be the cause of oil being pushed into the cylinder from a plugged air filter.

Don’t forget to check for oil burning off the muffler or engine from an oil leak or spilling oil when performing an oil change.

Black Smoke

Black is associated with excess fuel burning. This is due to a plugged air filter allowing the ratio of fuel to air to have a higher fuel concentration.

When the Bad Boy mower runs rich, it can emit black smoke. If the air filter is not the cause, look for another air restriction in your mower.