Lawn mower white smoke: How to fix it

If you own a lawnmower, then chances are at some point you will experience smoke coming from it. While this experience isn’t a guaranteed one, more often than not, lawnmowers produce white smoke.

There is no need to panic as most times, lawn mower white smoke means that your mower needs a little time out. There are various ways to handle the white smoke issue. This article provides you with the necessary information you need to fix your lawnmower and get it back on your lawn in no time. Read on!

What Causes Lawn mower White Smoke?

There are plenty of reasons why your lawnmower can produce white smoke from its exhaust. Some of the reasons include:

  • A worn-out engine
  • Overfilled oil
  • Failure of the head gasket
  • Tipped mower

Tipped Mower

The reasons outlined above are some of the most common reasons why your lawn mower could be blowing white smoke. However, a tipped mower is, in most cases, the reason why your mower could be producing the fumes. You may have tipped your mower to unclog the chute, to change the blades, or clean out the deck.

Another reason would be using your mower on a very steep surface. Both of these scenarios may cause the cylinder to fill up with oil. Once your cylinder fills up, restarting the mower causes the oil to burn, making your mower a chimney.

Fixing this issue is simple. Clear the mower off any oil and let it idle for a while. Allowing it to idle enables the engine to rest, and the smoke will eventually clear itself out. If you are unaware of the correct way to tip over your mower, you can always check in your manual. It is also advisable to avoid surfaces that are steeper than a 15-degree angle.

Overfull Oil Reservoir

If you want your mower to last longer, then engine oil should be your go-to. Engine oil sees your mower running smoothly and efficiently. Changing the oil regularly is a part of the maintenance of the mower. However, it is always advisable to know the right amount to put in.

Putting in less than the required amount can be a disaster while putting in excess can also cause you problem. The former causes friction due to a lack of enough lubrication. The latter causes the oil to enter the cylinder and causes burning along with the fuel.

Too much oil in the lawn mower also poses the risk of an oil leak, which isn’t good news. Additionally, excess oil can also result in the crankset getting damaged, thus hindering its motion. Overfilling the engine with oil isn’t as bad as under filling it since, as mentioned above, under filling causes a lot of friction.

The way to fix this issue is to refer to the guide while refilling your engine oil to know the exact amount needed to avoid overfilling. Most lawnmowers usually require not more than 20 ounces of oil – Use a dipstick to measure the oil.

After getting to ¾ of the recommended quantity, add small amounts of the engine oil until you get to the quantity required. If you have put in excess oil, then the only thing to do is to drain the excess. It is, however, essential to note that using the wrong grade of oil can also cause white smoke or, in other cases, blue smoke.

Refer to the manual to be sure of the exact engine oil the manufacturer recommends to avoid the bluish-white fumes. If the mower is producing black smoke, then this means that there is a lot of air in the fuel.

Most times, a mower with a dirty air filter produces black smoke. This scenario is, however, a simple one to fix as you need to remove the filter and clean it out. To ensure the filter is clean, it is advisable to use water and soap. Another alternative would be to replace the filter with a new one.

A Damaged Head Gasket

Damaged Head Gasket

The reasons so far outlined don’t require you to be worried about the condition of your mower. However, a damaged head gasket is something to worry about. A head gasket is a metal used to seal the cylinder. It is fitted to close the combustion chamber.

A puffing noise and a high crankcase pressure is usually an indication of a head gasket failure in addition to the white fumes. A faulty head gasket means that there is no seal on the cylinder, and therefore oil gets sucked into the combustion chamber.

As the engine oil starts getting into the cylinder, it can cause burning hence producing white smoke. If a lot of oil rushes to the cylinder, then the engine may fail altogether. The fix is usually to replace the gasket for a new one.

Gaskets aren’t repairable, and once damaged, they need to get replaced. If you have no previous experience with small engines, then it is advisable to call an expert to fix it for you

A Failed Carburetor

In case you’ve adjusted or fixed all the above, and there is still smoke coming from your mower, then you would need to adjust the carburetor. Changing it ensures there is a much leaner fuel to air ratio. A gas smell is a sure indication that your carburetor is damaged.

Before adjusting, always consult with your manual to be able to identify which screws should be used for the process. If you are sure that the carburetor is damaged, then replacing it may be the best alternative for your mower.

In Summary

There’s only so much you can do. If all the above steps do not fix the smoke situation, then that could indicate a more serious underlying mechanical issue. Continuous blue or white smoke could mean that some components of your engine or mower are entirely worn out.

Similarly, persistent black smoke could indicate critical mechanical issues. All these issues would require you to get a professional to intervene. If your mower is on warranty, you can get it fixed by your manufacturer. If not, you can visit a reputable repair shop and get it checked out.

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