Your Gravely Mower is Blowing Blue, Black or White Smoke: Find Out Why!

It can be quite alarming when you find smoke rolling out of your Gravely mower. The first thing that crosses your mind is “How much is this going to cost?” The last thing you want to spend money on is repairs on your lawn mower.

A Gravely lawn mower will start smoking when the air filter is plugged; the choke setting is incorrect; too much or too little engine oil is used in the crankcase; a bad engine gasket is leaking oil, or an internal engine problem developed with a piston ring or valve train failure.

When your lawn mower starts smoking, don’t continue to run the mower. Doing so can make a small problem develop into a much larger one.

I’ll help you try to identify the cause of your smoking problem. Hopefully, it is a quick repair and you don’t end up with internal engine damage.

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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.

This is Why Your Gravely Mower is Blowing White, Blue or Black Smoke

Blowing Black Smoke

Black smoke coming from your Gravely mower is typically a sign of your engine running rich. This means the ratio of gas to air being burned in the cylinder is higher than normal.

When you notice black smoke, check for items that can restrict airflow. These are things like a plugged air filter or an incorrect choke setting.

Blowing Blue or White Smoke

White or blue smoke coming from your Gravely mower is usually a sign your engine is burning oil. Follow the steps below to find reasons why this is happening to your mower.

It could be due to an incorrect engine oil level, worn piston rings, valve train problem, bad engine gasket, or the wrong oil viscosity.

8 Reasons a Gravely Lawn Mower is Smoking

Plugged Air Filter

With the amount of dirt and debris that gets tossed in the air when operating your mower, an air filter is an important component to keep dirt from contaminating the engine causing wear and damage.

An air filter must be cleaned or replaced regularly or it may become plugged keeping clean air from passing through the filter.

A reduced amount of air will cause your mower to run rich because the engine is receiving less air mixed with fuel. This will cause your mower to emit black smoke.

Another result of a plugged filter is oil in the cylinder. When airflow is restricted through the air filter, the engine may pull available air from the crankcase.

With this air, the engine will also pull oil into the cylinder. When the oil buns off the hot cylinder, it creates smoke.

I recommend starting each season with a new air filter. Your air filter maintenance doesn’t stop there.

You must check and clean it several times throughout the mowing season. Never run your mower without an air filter. Doing so only puts you at risk for potential engine damage.

Clean a Gravely mower paper air filter

• Remove the air filter from the air filter housing.
• Wipe out any dirt remaining in the housing and filter cover with a clean dry cloth. Don’t allow any dirt to fall into the air intake.
• Tap the filter against a solid surface to knock it loose and remove as much dirt as possible. Don’t use compressed air as it can damage the filter.
• Hold up your filter to a light source to see if the light is shining through the paper.
• Reuse the filter if you do see light through the paper. Install a new filter if you cannot see light, it is covered in oil, or the filter is damaged.
• Install the air filter and reattach the filter housing cover.

Incorrect Choke Setting

When your choke setting is not correct, you can experience black smoke. A choke that is left in the on position, or one that sticks remaining in the on position, will reduce the amount of air the engine receives.

This will cause black smoke to emit from the mower because your Gravely’s engine is running rich. Check the choke setting. Lubricate the choke cable so it moves freely and no longer sticks. Replace a damaged or worn choke cable.

Low Engine Oil Level

You may have not put enough oil in the crankcase when you completed your last oil change. It could be you are using the wrong oil viscosity or you have developed an oil leak leaving you with a low engine oil level.

Having a low engine oil level in the crankcase will not provide the lubrication needed for the internal engine parts to move freely. Friction will begin to build increasing the heat.

This heat can become so intense that the oil begins to burn and smoke. The engine parts may also begin to melt.

If a low oil level is a reason your Gravely mower is smoking, you can attempt to correct the problem by adding fresh oil. Most likely, this will not help. If your mower started smoking because of a low oil problem, you probably causes significant engine damage.

Bring your mower to your local Gravely dealership or small engine mechanic to be diagnosed. You will then need to make the decision as to whether your engine can be repaired or replaced.

Depending on the age and hours of your mower, you may even choose to replace it.

Too Much Oil

Filling your Gravely mower with too much engine oil can increase the pressure in the crankcase. This can cause oil to get pushed into the cylinder or even up to the air intake through the valve train. Oil will begin to burn off when the engine gets hot and emit smoke.

Replace the air filter if you find it covered with oil. Next, correct the engine oil level to bring it to the full level as indicated on your oil dipstick. You can remove a little oil by quickly removing and replacing the drain plug.

If your mower doesn’t have a drain plug, tip the mower on its side to remove a little oil from the oil fill area. Keep the air filter and carburetor on the high side of the mower when tipping it.

I prefer to use a turkey baster, like the one in your kitchen, or an oil evacuator to suck a little oil out of the oil fill area. To me, this is the easiest and cleanest method.

Bad Engine Gasket

A failing gasket can cause oil to leak from the engine. This oil will begin to smoke when it burns off the hot engine or muffler. You must locate the bad gasket and replace it. The difficulty of this task depends on the location of the failed gasket.

Piston Ring Problem

A quick check you can perform that may indicate you have an internal engine problem is looking for oil on the spark plug. When you find oil on the spark plug, I advise you to take the Gravely mower to an experienced small engine mechanic for diagnosis.

Excessive oil on the spark plug indicates you may have a piston ring or valve train problem. Either problem will result in having to take the engine apart.

You may find a scoring inside of the cylinder wall or worn rings causing oil to enter the combustion chamber and burn off.

If you have this type of problem, you may have to make the choice between replacing your engine or buying a new mower.

Valve Train Probleme

A valve train problem is not always the worse problem to have. The only way to detect this is by removing the cylinder head and performing a leak-down test. This should be performed by an experienced mechanic.

A problem with the valve train can develop when the valve gets burned by being overheated. The heat can cause the edge of the valve to fall apart.

This is known as a burnt valve. An indication you have a burnt valve or timing problem is a muffler that is glowing red due to extreme heat.

The valve and seat will have to be cut at certain angles to make sure the valve seats correctly. It needs to make good contact with the engine block to complete the combustion chamber.