Craftsman mower oil leak. Solved! What to Do When Your Lawn Mower Starts Smoking

A smoking lawn mower is never a good sign. Whether the smoke is blue, white, or black, here’s how to identity and address the issue without the help of a professional.

By Glenda Taylor and Bob Vila | Updated Sep 24, 2020 1:40 PM

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Q: Recently, my mower started billowing smoke when I powered it up, so I shut it off immediately. Why is my lawn mower smoking? And is it a fire hazard? I want to know how to proceed so I don’t harm the machine.

A: Your lawn mower can emit smoke for numerous reasons—many of which don’t require the services of an expert. A homeowner can usually identify the reason for a smoking lawn mower by gauging the color of the Cloud coming around the engine, then fix it accordingly before lasting damage occurs. Keep in mind that all mowers with internal combustion engines contain the same basic parts, but the configuration of those parts varies widely, depending on manufacturer and model. Consult your owner’s manual if you’re unsure how to access a specific part of your lawn mower’s engine.

White or blue smoke may indicate an oil spill on the engine.

If you’ve recently changed the oil in your mower and the engine is emitting white or blue smoke, it’s possible that some of the oil spilled onto the engine. Similarly, you could’ve spilled oil on the engine by mowing on a slope greater than 15 degrees or tipping the mower on its side. The smoke may look disconcerting, but it’s completely harmless. Solve the problem by restarting the mower and allowing the spilled oil to burn off. If you tip the mower often for cleaning or maintenance, check your owner’s manual to determine the best way to reduce the risk of oil leaks.

An overfull oil reservoir may also cause white or blue smoke.

Ensure you didn’t overfill the mower by checking the oil level with the dipstick located on the reservoir. To do this, remove the dipstick cap, wipe off the stick with a rag, and reinsert it into the reservoir. Then remove the dipstick once again and determine the oil level in comparison to the recommended “fill” line on the stick. If the level is too high, drain the oil (consult your owner’s manual for instructions), then refill the reservoir with it. Start checking the oil level with the dipstick after you’ve added about ¾ of the amount recommended in the manual. Continue to add small amounts of oil until the level matches the recommended “fill” line. Also note that using the wrong grade of engine oil may cause blue or white smoke. Consult the owner’s manual for the exact type of oil recommended for your mower.

Black smoke may indicate that the mower is “running rich,” or burning too much gasoline.

Your lawn mower’s carburetor regulates the ratio of gasoline to air mixture. If the carburetor isn’t getting enough air, the mixture has a higher percentage of gasoline, which can create black exhaust smoke. It’s possible that a dirty or clogged air filter is preventing sufficient airflow into the carburetor. Try replacing the air filter. (Note: air filters vary by mower model; view example air filter on Amazon.) Next, run your lawn mower for a few minutes. If the black smoke still appears, the carburetor might need to be adjusted in order to increase airflow. Either take the mower to a professional or adjust the carburetor yourself with instructions in your owner’s manual.

Take your mower to a repair shop if necessary.

If the previous steps don’t correct blue or white smoke, your mower could have a more serious problem, such as an air leak in the crankshaft (the cast iron or cast aluminum case that protects the moving parts of a mower’s engine). Continuing blue or white smoke could also indicate that some of the engine’s components or seals are worn out and need replacement. Similarly, if black smoking still persists after you’ve replaced the air filter and adjusted the carburetor, you could be facing a more serious mechanical issue. All of these problems require the help of a professional. If your mower is still under warranty, check with the manufacturer for the location of the nearest servicing dealer; problems stemming from a factory defect or poor workmanship may garner free repairs. If your mower is not covered under warranty, a reputable small-engine repair shop should also be sufficient to get the job done.

Why is My Lawn Mower Smoking?

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Leaking oil from the exhaust is the usual cause of blue, white or black smoke from a lawn mower. Learn to assess and fix a sputtering, smoking lawn mower.

Gas-powered lawn mowers can be full of surprises. Perhaps the most startling one happens when you pull the mower cord and the engine sputters into action, only to be followed by clouds of smoke from the motor and under the mower deck. What’s going on and what should you do about it?

Why is My Lawn Mower Smoking?

There are several reasons your lawn mower could be bellowing out smoke. While it looks kind of intimidating, like something bad is about to happen, in most cases, it’s nothing to be worried about, and it’s not usually hard to fix.

Oil spilled onto the engine: If you changed your lawn mower’s oil recently or added more to the oil reservoir, some may have spilled out onto the engine. Mowing on a steep slope in the yard, or turning it over to adjust the blade, could also cause some oil onto the engine. When that happens, the oil will burn off, causing blue or white smoke. It’s best just to let it burn off, so when you start up again, the oil will be gone.

Overfilled oil reservoir: Too much oil in the reservoir can also cause a lawn mower to smoke. The lubrication systems in most mowers are not well sealed, and usually there’s an overflow oil reservoir with a relief outlet where excess oil can leak. Check the oil level in your mower, and if there’s too much in there, consult the manual for how to drain some out until it’s back at the proper level.

Mower burning too much gasoline: The carburetor regulates the ratio of gasoline and air in a lawn mower engine. If the carburetor isn’t getting enough air, that means the mix is heavy on gasoline, which can cause black smoke from the exhaust. Often times that’s caused by a dirty air filter, which is preventing enough air from getting to the carburetor.

Different Types and Colors of Smoke

If the smoke is black, there may be an engine problem behind the smoke. In such cases, your first step after the mower cools down should be to check the air filter. If it’s clogged, the combustion chamber may not be getting enough oxygen, resulting in a too-rich fuel mixture that will cause the engine to run poorly and even spew smoke. The solution is to change the air filter, a relatively easy task.

Blue and white smoke is the result of oil on the engine. If there’s too much oil in your oil reservoir, you may want to drain some of it out. If it’s just some oil spilled onto the engine, all you have to do is let it burn off.

When to Take a Smoking Lawn Mower to the Repair Shop

If your smoke problems persist, chances are the oil seals in the engine lubrication system or around the pistons are the issue, or you may even have a cracked crankcase. These are repair jobs for a small engine pro, unless you’ve got experience working on engines.

There is also a chance the smoke is simply the result of a carburetor that needs cleaning or adjusting. If you’re up for it, most owners’ manuals include instructions on how to adjust and clean the carburetor.

Remember, it’s important to tune up your lawn mower at the start of the season, which will help make sure it’s running properly and prevent potential problems like a Cloud of smoke following you around the yard.

Troubleshooting and Fixing the Mower

Mark Johanson is an experienced home and garden writer/editor/publisher. He has written several books and hundreds of magazine articles. He has edited and directed more than 400 DIY and gardening books, including the BLACKDECKER® Home Improvement Library series and two of the best-selling gardening books in North America. He is an experienced DIYer and enthusiastic gardener.

Why Oil Is Leaking Through Filter in Lawn Mower

Lawn mowers are machines that cut grass. A lawn mower is a machine that is used to cut grass and weeds in the landscape, typically on private property. They are tools that help us to clean up and maintain the lawn.

They come in different types and sizes, depending on their intended purpose. Most of the lawn mowers have metal blades and are powered by an engine to propel them through the grass.

Sometimes these machines get problems. Such problem is oil leaking through the filter of the mower. Oil leaking in lawn mower is a common problem for many homeowners.

While the oil dripping onto the ground is not easy to remove, there are some precautionary measures that can be taken to prevent it. In this article we’ll be discussing about the issue and the possible fixes regarding the issue.

Reasons behind oil leaking

Many homeowners are not aware of the reasons behind oil leaking in their lawnmower. Some of these reasons include an oily filter, overfilled crankcase, and an oversoaked air filter.

These are major reasons why oil leaks occur in your mower, and they can be easily prevented with proper maintenance. Some of the major internal problem can also cause this issue.

Oily Filters

One of the most important parts of a lawnmower engine is the filter. The filter traps dirt and particles from being mixed with gasoline and combusting.

If the filter gets clogged with oil, it can cause oil to leak through the filter and into your engine. The oil filter on the lawn mower is trapping dirt and mowing grass particles.

This eventually leads to a buildup of oil in the engine and potentially causes a fire. An oily filter can also cause inconsistencies in your engine, which can result in poor performance, as well as cause damage to the mower itself.

It is important for you to keep this debris out of your engine’s cylinders by periodically changing your filter. It’s not easy to find a replacement for an old lawnmower engine so it’s important that you keep an eye on your mower’s filter.

You should know how to change your lawnmower oil every year and make sure that your mower is in good shape.

Incorrect Procedures

Turning the mower over the wrong way is dangerous for both the operator and for the machine itself. There are several reasons why this might happen, one of which is when blades from underneath the mower deck can cause oil to leak from the filter.

The process of turning the mower over the wrong way was to turn the mower with the air filter down. This created a situation where oil leaked through the filter and onto blades underneath.

The oil leaks through the filter causing a mess for your lawn and can damage other parts of your machine as well. It’s important to keep your mower in good working order by taking care of it when you use it.

Overfilled Crankcase

Crankcase is the housing where an engine’s crankshaft is located and contains the entire crank mechanism. A crankcase is made up of a number of parts. It also has a complex cast part which includes pistons, cylinders, and connecting rods.

A crankcase is necessary for any engine to work properly. The crankcase creates the pressure needed for oil to flow through each cylinder and cooling channels are required for proper vehicle operation.

The crankcase is typically small and can be easily overfilled by a small amount of oil. When this happens, the excess oil will drop down into the filter or breather tube and cause damage.

Oil enters the engine through the carburetor, travels through the other internal components and ends up in the air filter. Oil can cause damage to some of other components if not cleaned up regularly.

Add a little oil to the crankcase, then check the oil dipstick and add more if needed.

Oversoaked Air Filter

Oversaturated air filter with oil is very dangerous to the mower. Oil can leak out of the air filter and clogs the engine. This process will cause a lot of damage to the lawn mower and the engine.

The best option is to replace the air filter, which will stop oil from leaking through it and the lawn mower. The oil that leaks out of the air filter ends up coating other parts on your lawnmower like the engine, carburetor, etc.

So, if you do not replace your filter often enough, your lawnmower will eventually break down because too much oil is being sucked into it.

To avoid oil leaking through an oversoaked air filter, make sure you change them once per season or when they get clogged with dirt or debris. Also, you must clean the carburetor as needed.

Internal Problems

Sometimes oil leak occurs because the internal problems caused by worn parts, blown head gaskets, and damaged cylinders. Internal problems cause oil to leak through filters in lawn mowers.

If you experience these problems, contact a small-engine specialist to fix these issues for you before they become more serious. They might need more expensive repairs such as a blown head gasket or damaged cylinder worn cylinder rings.

Sometimes you might need a small-engine specialist to repair a lawn mower with a faulty oil filter.

If you are looking for a small engine specialist to help with your lawn mower, make sure they use quality oil and filters and that they understand your equipment before they start servicing it.

The engine needed new cylinder rings and a new gasket for oil from entering properly into the engine again.

Tipped Lawnmower

Most lawnmowers come with a filter that prevents dirt into the engine. When the lawnmower is tipped over, oil can leak through the filter.

A tipped lawnmower can cause oil to leak into the engine and air intake when it is running. Filters may also become clogged with debris that builds up over time.

This can lead to a variety of issues with engine performance, breakdowns, and emissions issues. This causes engine misfiring and damage to other parts as well.

In this case, it can cause oil to leak from the crankcase into the breather tube. Tipping over a lawnmower can cause oil to flow towards the carburetor which can cause significant problem by clogging up oil in air filter.

To prevent this from happening, always be mindful to keep your lawnmower in good condition and clean by checking it after every use for signs of wear such as dents or dings.

Conclusion

Oil leaking in a lawn mower due to any of these problems is a common issue faced by homeowners worldwide. To prevent this issue, it is important that you follow proper maintenance procedures before using your mower for its intended purpose.

The problems that you need to fix are not as easy as it may seem. Sometimes, the solution can be even more complicated and time-consuming than the problem itself. Then you need professional help to fix this.

Your Craftsman Mower is Leaking Gas: Solved!

Walking into your garage and getting overwhelmed with the smell of gas fumes can be alarming.

You look around and identify the fuel smell is coming from your Craftsman lawn mower, but you can’t find the source of the fuel leak because, unlike oil, fuel tends to evaporate and doesn’t leave big stains underneath the leak.

Craftsman lawn mowers may leak gas when components of the carburetor fail or become stuck; the fuel lines, filter, or pump deteriorate; the gas cap doesn’t seal correctly, or the fuel shut-off valve fails.

So, unless your fuel leak is leaving a significant puddle, it can be pretty hard to find where it is coming from. I have shared a list of items that can cause your Craftsman fuel leak.

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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 Why Your Craftsman Lawn Mower Leaks Gas

Craftsman mower parts that are vulnerable to leaking gas:

• Carburetor
• Fuel Pump
• Fuel Filter
• Fuel Lines
• Fuel Tank
• Fuel Shut-Off Valve
• Primer Bulb
• Gas Cap

Craftsman Carburetor is Leaking Gas

Gasket failure in the carburetor bowlThe carburetor bowl is located at the bottom of your carburetor. This is where some fuel is stored and used to keep your engine running after it leaves the gas tank. You will find a rubber Band-looking gasket between the base of the carburetor and the bowl that could be your problem.

Your lawn mower may be leaking fuel out of the bottom of the carburetor because the gasket failed between the carburetor and bowl.

This gasket is prone to becoming dry and brittle because it is located near the engine where it is consistently exposed to hot conditions when the engine is running and cool conditions when it is not. This constant warming and cooling make the gasket fail to seal.

Replace the rubber gasket when you identify a leak out of this area of the carburetor. It is a pretty simple repair.

Begin by shutting off the fuel to your mower by turning the fuel shut-off valve, if your mower has a valve, or use clamps to stop the fuel flow. Once you have stopped the fuel flow, remove the screw and remove the bowl.

Have a rag in your hand to catch any fuel in the bowl. Replace the gasket and reinstall the bowl and the screw. Turn the fuel back on and wipe down the carburetor bowl.

Inspect the carburetor to make sure you don’t have any more leaks. If you do find leaks, continue to check the carburetor by inspecting the float and needle.

Stuck carburetor floatCheck to see if your fuel leak is coming from the air intake port. If you find a leak in this area, most likely it’s the result of a stuck float. The float is the part of the carburetor that regulates how much gas is allowed into the bowl.

If the carburetor float does get stuck, it won’t stop fuel flow and excess gas will begin to run out of the carburetor.

If this is what is happening to your carburetor, you will need to take it apart to see what is causing your float to stick. Read the procedures for cleaning the carburetor in this article.

Stuck float needleThe float needle works with the float to keep gas flowing to the bowl. Sometimes the needle will get stuck. You can try to “unstick” the needle by hitting the side of the carburetor gently with the handle end of the hammer.

This may work a time or two to get your carburetor working again, but it will continue to happen and your carburetor will need to be rebuilt or replaced.

You can buy a carb rebuild kit and repair it yourself or have your local mower repair shop rebuild your carburetor.

Craftsman Fuel Filter Cracked or Deteriorating Causing a Leak

Because an inline fuel filter is made up of plastic and fuel consistently sits in the fuel filter, the plastic can become soft and begin to leak. A leaking fuel filter needs to be replaced.

Bad Fuel Pump Can Begin Leaking Gas

Most fuel pumps on a Craftsman are made of plastic. Not all mowers use a fuel pump. Your Craftsman will use one if the carburetor sits higher than the fuel tank.

The fuel pump will pump fuel up to the carburetor. The plastic can crack, begin seeping at the seams and deteriorate from running old fuel.

Rusted or Failed Seams on Your Craftsman Fuel Tank Will Begin to Leak

Most fuel tanks today are made with high-density polyethylene. Eventually, the seams on the tanks can fail causing your fuel tank to leak. If you have a much older Craftsman mower, your mower may be using a metal gas tank.

The challenge with metal gas tanks is they can develop a rust hole. You must replace your gas tank if you have a poly tank with a leak in the seam or a metal tank with a rust hole.

Craftsman Fuel Shut-Off Valve is Prone to Leaking Gas

You may or may not have a fuel shut-off valve on the bottom of your fuel tank. This valve does exactly what its name indicates. It shuts off the fuel. Whether you have a metal or plastic fuel shut-off valve, both types are prone to leaking.

Old Craftsman Fuel Lines Can Become Dry and Leak

Bad fuel and weather elements can cause your fuel lines to become dry and cracked. You need to follow the fuel lines out of the fuel tank to check for wet spots.

Also, pay close attention to the area near the fuel line clamps as these can also puncture or weaken the fuel line.

I like to use worm gear style hose clamps instead of the pinched style because they are less prone to causing problems when pinching the lines to prevent fuel leaks. Any cracked fuel hoses must be replaced.

Cracked Primer Bulb Can Begin to Leak Fuel

Some lawn mowers use a primer bulb to prime the carburetor. Pressing on the bulb moves fuel into the carburetor. When the primer bulb becomes overfilled, it can begin leaking.

It can also leak when the bulb’s plastic begins to wear and crack. Another place to check for a leak is where the bulb meets the fuel line.

Bad Craftsman Gas Cap Seal Can Cause Leaking

If you’ve gotten to this step and haven’t found a leak, there is a good chance your gas cap could be the cause of the leak.

When gas fumes fill the garage and you can’t find the leak, it is possible the leak is out of your fuel cap. The fuel evaporates before you can find a wet spot on your mower.

The seal around your Craftsman’s fuel cap can fail to allow gas to leak out of the edges of the cap. A good way to check for a bad seal on your cap is to rock your mower back and forth to splash fuel up to the cap and check for signs of a leak around the base of the cap.

If you find the cap isn’t sealing correctly, you must replace it. You can find Craftsman gas caps online or go to your nearest Craftsman servicing center.

Still Having Problems With Your Craftsman Lawn Mower?

It would be nice to own a mower that will never give you problems. However, they don’t exist. Own a lawn mower long enough that you are bound to run into problems.

The most common of them are problems with starting, smoking, dying, vibrating, and cutting.

I put together a handy guide to help you quickly identify items that can cause a problem in your riding mower, zero turn, and push mower along with ways to solve them. You can find this guide at Common Craftsman Lawn Mower Problems Solutions.

If you are unsure how to safely perform diagnostics and repairs on your lawn mower, 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 lawn mower dealership or lawn mower repair shop will be able to help you solve your problem.

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