How to stop a lawn mower from smoking

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In an ideal World, white is the color of peace, blue is associated with depth and stability while the black color represents strength, power, seriousness, and authority.

However, for a smoky lawn mower, these colors have a whole new meaning and they could indicate a troubled machine.

Below we look at what every color symbolizes and more importantly, how to stop a lawn mower from smoking.

What a white smoke tells you

The good news first: you shouldn’t lose sleep because of white smoke for the simple reason that it generally doesn’t indicate a weighty problem.

But what does the white vapor coming from the mower exactly mean?

Well, the cloud of white smoke you’re seeing simply tells you that the engine is actively burning oil due to some reason (more on this next).

Causes of white smoke

The causes of the white smoke can vary although it’s pretty common for mowers to produce white exhaust smoke if there’s too much oil, for instance, in the crankcase or low-quality oil grades have been used.

The other commonest cause is worn out or damaged cylinder/piston rings.

Finally, the issue may arise because of the following factors:

  • Air Leaks in the crankcase.
  • The crankcase breather is faulty.
  • You’re running the engine while tilted above a 15-degree angle, causing oil to escape from the crankcase.
  • You have exceeded the standard engine’s oil capacity.
  • Something is obstructing the breather tube (this is usually found behind the engine’s air filter).

How to stop a lawn mower from smoking white

As explained earlier, thin white vapor shouldn’t be a matter of huge concern and in fact, sometimes the white smoke disappears on its own – just let the lawn more run.

On the other hand, thicker white smoke may be pointing towards a pretty big issue.

For example, it may signal that oil has trickled into the combustion chamber and the engine may develop further problems including starting to stop suddenly.

On a positive note, you can easily prevent such problems by taking simple actions.

Here are simple troubleshooting hacks you can implement and get rid of the white smoke (and save on potentially costly repairs):

1.      Correct the tilting angle

Check if you might be tilting the engine beyond a 15-degree angle and reduce the incline.

Even mowing on climbs can make oil spill into the critical combustion chamber so try to mow climbs at the correct angle.

Note: If you must tilt the engine, check that the spark plug will be facing upwards. This helps block oil from leaking off the crankcase.

2.      Check and seal any oil leaks in the crankcase

Inspect the crankcase and seal all the possible oil leaks you notice.

3.      Pour the right type and grade of oil

This applies where you’d used the incorrect grade/type of oil.

Also, put the right volume (track with the dipstick) and proper gas to oil ratio where necessary.

4.      Inspect the rings, cylinders, and head gasket

Check the condition of the piston rings, cylinder, and the head gasket and replace as appropriate (these are repairs are more difficult).

Tip: New mowers will sometimes release white smoke when started for the very first time because manufacturers often leave oil residues in the machine. No action is needed from you in this case- simply allow the mower to run and burn off the entire residue. The smoke will go away.

What the black smoke tells you

For the most part, a mower exhausting black smoke is not a good sign.

So, what does the cloud of black smoke exactly mean for mowers?

Simple! Black smoke mostly indicates that a mower is at that moment burning extravagant amounts of gas as the gasoline-air ratio is “too rich”.

For starters, this means there’s insufficient air in the carb, a situation that causes the combustion to be done partially.

Actually, it is the unburnt gas that is exhausted as black smoke.

Causes of black smoke

Black smoke may be triggered by a dirty carburetor but is more often caused by a clogged air filter.

The other suspect is problems in the choke or bad carburetor settings.

The worst part is that the mower struggles to start and sometimes completely refuses to fire in this state. 

How to stop a lawn mower from smoking black

You have super easy fixes here.

  1. Clean the filter

Just pull the filter out and clean it using soap and water.

Consider installing a new filter if you deem it fit.

Note: Paper filters need to be replaced and not cleaned (They are never built to be cleaned).

  • Adjust the carb

If the smoke has not gone away, adjust the carb to make the fuel mixture leaner.

There are two adjustment screws located outside the unit; one to adjust the idle and the remaining one the fuel mixture.

Consult the owner’s manual for adjustment procedure.

  • Check the Choke

The gasoline mixture will also be too rich if there are problems with the choke.

It may, for example, fail to open even after the engine has started messing the balance of the gasoline mixture.

For this reason, be sure to check every other linkage to the choke and undertake the required repairs.

Make sure it’s not being hampered by dirt as well.

What the blue smoke tells you

Overall, the blue smoke is closely related to the white smoke and would point to extreme oil consumption, oil-soaked air filter, a clogged breather, or rings failure.

How to stop a lawn mower from smoking blue

We shall not devote a lot of time to blue smoke because it’s trouble-shooted in a similar manner to the issue of white smoke.

Go ahead and implement the procedures we had discussed in the white smoke section and see if you’ll succeed in eliminating the blue smoke if your mower is a victim.

Final notes

Because mowers’ engines are not designed identically, we recommend that you refer to your owner’s manual before undertaking any of the above hacks/maintenance tasks.

Also, remember to put on the right protective gear as advised in your specific model’s manual (good practice dictates that you protect yourself anyway).

Lastly, you should involve a professional if unsure of any of the highlighted procedures or if the smoke keeps coming back. 

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