Skip to Content

Hustler Mower is Blowing Blue, Black, or White Smoke: SOLVED

The best thing to do when you start seeing smoke is to stop mowing and shut off the engine. Troubleshoot the problem to avoid causing potential additional damage.

A Hustler lawn mower may begin smoking when the air filter is plugged, the engine oil level is incorrect, an engine gasket is bad, or you have developed an internal engine problem with the valve train or piston ring.

Remove the ignition key and spark plug wire before performing any repairs. Wait for the engine to cool and all moving parts to stop for your safety. Follow additional safety precautions found in the Hustler operator’s manual.

Kohler engine on a zero turn

This post may include affiliate links. Purchases made through these links may provide a commission for us, at no extra cost to you. As an Amazon Associate, we earn from qualifying purchases.

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.

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

I always recommend going through the steps in the next section 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

  • Associated with the burning of excess oil.
  • Oil is burning off in the combustion chamber from damaged piston rings or valve train.
  • Engine gasket oil leak.
  • Oil is being pushed into the cylinder from a plugged air filter.

Black Smoke

  • Associated with excess fuel burning.
  • A plugged air filter allows the ratio of fuel and air to have a higher fuel concentration. When the mower runs rich, it can emit black smoke.
  • If the air filter is not the cause, look for another air restriction in your mower.

Reasons Your Hustler Zero Turn Lawn Mower is Smoking

Plugged Air Filter

With the dirt and debris that gets tossed into the air while operating a Hustler zero-turn, it’s important to inspect the air filter regularly.

This is because dirt can plug the air filter so the engine no longer gets the air required which may cause it to begin smoking.

First of all, never run your mower without an air filter, not even if it’s for a short while you wait for a new replacement air filter.

Without a filter, dirt, and debris can get to the engine through the air intake causing damage to the cylinder and engine seals.

Second, always run your mower with a clean air filter. I find it’s best to start each mowing season with a new air filter and clean it several times throughout the season.

It only takes a couple of minutes to check the filter before you run your mower. Taking time to do this can save you from costly damage to the engine.

When the air filter is extremely dirty, covered in oil, or damaged, you must replace it.

Why does a plugged air filter in your Hustler lawn mower cause it to smoke?

  • 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 too much fuel is burned during the combustion process.
  • 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 a Hustler mower begins to smoke, the air filter can become plugged with smoke making your engine problem worse.

Clean a Hustler paper air filter element

  • Remove the filter from the air filter housing.
  • Wipe out any dirt remaining in the housing with a dry clean cloth. Do not allow dirt and other particles 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. The filter should also be replaced when you find it covered in order, extremely dirty, or damaged.
  • Install the air filter and attach the air filter cover.

Insufficient Engine Oil

The amount of engine oil the manufacturer requires is not a suggestion. The correct amount of oil must be used to keep the oil level at the “full” line as indicated on the dipstick.

Having a low or high engine oil lever can not only result in a mower that smokes, but it may also cause significant engine damage.

Engine Oil Level is Too Low

Not having enough engine oil in a Hustler mower crankcase can have catastrophic effects. When the engine oil level is low, it doesn’t provide the lubrication for the engine parts to move freely.

Friction will begin to build which causes the engine to increase in temperature. The engine can become so hot that oil begins to burn and the internal engine parts begin to melt creating smoke.

If this happens to your mower, you can attempt to change the oil and add fresh oil to the correct level. However, this most likely won’t solve the problem because the engine was most likely damaged when it became so hot that it began to smoke.

I suggest taking the mower to a Hustler mower dealership or a trustworthy small engine mechanic near you.

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

Most people know it’s not good to run the engine when there isn’t enough oil in it, but many people don’t know you shouldn’t run more oil than required in the crankcase.

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.

For additional problems, check out this article for problems you may encounter from running your Hustler mower with too much oil.

When you find too much oil in your crankcase, correct the engine oil level by removing a little oil. You can do this through the drain plug or oil filter.

You can also use an oil evacuator or turkey baster to extract a little oil from the oil fill area.

After removing a little oil, recheck your engine oil level using the dipstick. Continue to add or remove oil until the level is at the “full” level.

Check the 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 Hustler mower 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.

Replace a bad gasket. This varies in difficulty depending on the location of the bad gasket.

Internal Engine Damage

Internal engine problems that you cannot see can cause a Spartan mower to smoke. Once you have reached the point where you are looking for an internal reason for smoking, it becomes increasingly difficult.

Identifying the exact cause of an internal engine problem will not be possible without tearing down the engine and performing leak-down and compression checks.

However, there is one simple check that may signify you have an internal engine problem, but it won’t tell you the exact problem.

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.

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.

A small engine mechanic will be able to diagnose the engine and find the root cause of the damage.

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 Hustler to start smoking.

Valve Train Problem

A Hustler 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.