It can be quite alarming when smoke starts rolling out of your Snapper lawn mower. The best thing to do is shut your mower off if it didn’t already overheat and quit. Do not run your mower until you determine what type of smoking issue you have so you don’t cause more damage.
Not all smoke coming from your mower is a sign of a catastrophic failure. It can be something as simple as excess gas burning or a more severe problem like melting internal engine parts.
A Snapper lawn mower begins smoking when the engine has an insufficient engine oil level, plugged air filter, or a bad engine gasket allowing oil to leak.
Smoking can be the result of an internal engine problem including a valve train or piston ring problem. Smoke can also emit from your Snapper mower when it is burning a high concentration of fuel.
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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 Snapper Mower is Smoking
Air Filter is Clogged
It is important to run a clean air filter in your Snapper lawn mower. Without a filter, dirt can get drawn into the engine and cause significant engine damage.
Your mower not only needs air to run, but it also requires that air be clean and without debris, so always run your mower with an air filter.
This air filter must be kept clean. I recommend replacing your air filter annually. Then check and clean your filter several times throughout the mowing season. Clean the mower frequently when you are mowing in dusty conditions.
When the air filter isn’t kept clean, it will become plugged with dirt and debris that will prevent air from passing through the filter. This could result in smoke coming from your Snapper for one of these reasons:
- Your 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 Snapper 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 paper air filter element
- Remove the filter from the air filter housing.
- 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 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
Your Snapper mower’s engine manufacturer requires a certain amount of engine oil in the crankcase. This is not a recommendation. It is a requirement.
Having too much engine oil or too little engine oil in your mower can result in a costly repair bill or even an engine replacement.
Engine Oil Level is Too Low
A low engine oil level won’t give your internal engine parts the lubrication they require to move freely. When there isn’t enough oil, friction begins to build which causes your engine to get hot. It can become so hot that the oil begins to burn and engine parts begin to melt creating smoke.
Once you find your engine is smoking because of low engine oil, you can attempt to add fresh oil and run your mower.
Chances are, if your mower became so hot it began smoking because of low oil, you have caused engine damage that can’t be easily solved by correcting the engine oil level.
You are better off bringing your mower to an experienced small engine mechanic to be diagnosed.
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? 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 Snapper 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.
Smoke coming from your Snapper 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 Snapper 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 in Your Mower’s Engine
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 Snapper to start smoking.
Valve Train Problem in Your Mower’s Engine
A Snapper 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.
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 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.
Black Smoke 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 Snapper mower runs rich, it can emit black smoke. If the air filter is not the cause, look for another air restriction in your mower.
Still Experiencing Problems with Your Snapper Lawn Mower?
Own a lawn mower long enough, you’ll start running into problems with it starting, not continuing to run, smoking, leaking gas, giving a bad cut, vibrating, or another issue.
To help you save time and money, I have put together a guide to help you troubleshoot the next problem that develops on your Snapper mower.
You can find this guide at Common Snapper Lawn Mower Problems & Solutions.
If you are unsure how to perform diagnostics and repairs on your lawn mower safely, it’s best to have a professional complete the repairs.
This will help you avoid personal injury or additional damage to the mower. Your local Snapper lawn mower dealership or lawn mower repair shop will be able to help you solve your problem.