Has your lawn mower gone up in smoke?
If there’s white smoke coming from your lawn mower, don’t freak out!
There are two common causes – spilled oil or too much oil – and both have simple solutions. You’ll either need to burn off the oil on your engine, or drain some oil from your reservoir.
Is your lawn mower smoking white? Here’s what that means and what you can do to fix it.
Why is My Lawn Mower Smoking?
There are a lot of different reasons for your mower to spew smoke.
Common causes include excess oil, a blown head gasket, not enough air in the gas tank, or a dirty air filter.
Is white smoke from a lawn mower dangerous? Not necessarily!
The causes are usually easy to fix, and as long as you take proper safety precautions, there’s minimal risk.
What Does White Lawn Mower Smoke Mean?
For lawn mowers blowing white smoke (or even blue smoke), the likely culprits are an overfilled oil reservoir or oil spilled onto the engine.
You may have overfilled your mower with oil, which then spilled over and caused engine smoking.
Alternatively, if you’ve been mowing on a slope greater than 15º or if you’ve tipped your lawn mower sideways to inspect the mower deck, the oil will spill.
It’s less likely, but valve issues could also lead to white smoke, particularly the fuel solenoid. If the solenoid or other valve is compromised – say, it’s stuck in an open position – that could cause fuel or oil to leak out.
For valve problems, the white or blue smoke will typically be accompanied by other issues, such as compromised acceleration or a backfiring mower.
If you’ve accidentally turned your lawn into a DIY rave, there’s no need to panic. White smoke is generally harmless and easy to fix.
Quick Fixes for a Smoking Lawn Mower
Step one, if there’s smoke from a lawn mower, is to shut off the engine immediately. Your safety is the main priority here, so turn off your mower until the smoke clears.
For electric mowers, take out the spark plug so you don’t risk a fire hazard.
After the mower cools and the haze is gone, check the air filter.
For a dirty or clogged air filter, you’ll need to clean it. For a worn-out air filter, you’ll likely need to change it out.
If that’s not the case, replace the parts and restart the mower. Let it run for about 5–10 minutes to burn off any oil that could have entered the lawn mower engine.
If there’s no more blue or white smoke, you should be fine.
How to Fix White Smoke from Lawn Mower
If the quick fixes don’t work and you’ve run your engine for about 10 minutes, then it’s time to get down and dirty.
Identify the cause of your white smoke and use the appropriate solution.
White smoke from spilled oil
This is one of the most common reasons your push mower is smoking white.
Oil spills in mowers have a few common causes:
- Worn-out seals in the combustion chamber
- Cracked crankcase or air leak
- Mowing a slope of over 15º incline
- Tipping the mower on its side
- Overfull oil reservoir
- New mower with leftover oil residue
The excess lubricant will leak out onto the mower’s engine, where the oil burns and causes smoke.
In this case, just restart the engine and let it run. Eventually, all the oil will burn off and the engine will stop producing white smoke.
To stop this issue from reoccurring, target the source. Check the owner’s manual for ways to limit oil leaks.
If your lawn has a steep slope, consider levelling it so it places less stress on your mower.
But if you’ve tried everything and there’s still an oil or fuel leak, you may have to take your machine to a repair shop so they can inspect the valves and other components.
White smoke from too much oil
Double-check the oil level to ensure you didn’t overfill the reservoir.
Use the dipstick to check the engine oil (remember to wipe the dipstick clean first so you get a good reading). Compare the level to the “fill” line on the stick.
If the level is too high, you’ll need to drain oil from the reservoir. Follow the instructions in the owner’s manual for draining and refilling the oil to the fill line.
You may also be using the wrong grade of engine oil, which could cause lawn mower smoke.
Other Smoke Problems
The smoke from a lawn mower might not just be white – sometimes you’ll get blue or black smoke as well.
If that’s the case, here are some potential causes.
Black smoke
If you’re getting black smoke from your mower, the issue may be a too-rich fuel mixture.
The carburettor regulates the proportion of gasoline and air mixture, but if it’s not getting enough air, it causes black exhaust smoke.
The usual cause for this is a clogged air filter that’s limiting air flow. You may also need to adjust the carburettor.
Blue smoke
The causes for blue smoke are generally the same as white smoke – spilled oil or too much oil.
The smoke is simply a different colour, usually the result of higher combustion temperatures.
Maintain Both Your Mower and Your Lawn
If the smoke problems persist, or you discover a deeper engine problem that you can’t fix, it’s better to take your mower to a repair shop.
You may also need expert help to change the seals on the combustion chamber or fix an air leak in the crankshaft.
Check your lawn mower regularly to ensure everything is in working order, from the engine lubrication system to the oil seals.
Frequent check-ups let you catch malfunctions or damaged mechanisms before they can cause bigger problems.
Knowing how to tackle white smoke from lawn mower will save you some stress in the long run.
Not only will it help your mower last longer, but your lungs will be more thankful – and you’ll get fewer complaints from neighbours too!
