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Too much of anything is bad for you – and it’s the same for dogs, plants, and lawn mowers!

For that last item, too much oil in the lawn mower engine can cause quite a few problems. It can lead to overheating, stalling, or even engine damage. And of course, it’s a waste of oil.

Now, what are the symptoms of too much oil in a lawn mower?

If you’ve identified the problem, it’s also important you follow proper oil removal procedures so you don’t damage your mower.

After that, keep an eye on how much oil you pour into the engine. Think like Goldilocks – not too much, not too little, but just right!


What Happens If You Put Too Much Oil in a Lawn Mower?

top view of lawn mower on green grass

There are several reasons why excess oil is bad – especially for your lawn mower engine.

One of the bigger risks is that your engine can overheat. This will put extra pressure on the crankshaft and rod, which can bend or break, leading to expensive repairs.

Overheating can also cause the oil or gas to catch fire, or even damage the engine itself.

If the oil is leaking, it could enter the combustion chamber and prevent oil compression, which causes your piston rod to bend. Alternatively, if the oil gets through the engine cylinder, it’ll make your engine hydro-locked.

Additionally, excess pressure can cause the engine to blow its gaskets, valve seats, or bolts.

Lastly, it wastes a lot of oil – and no thrifty homeowner wants that!


Signs of Too Much Oil in the Lawn Mower

You’ll save yourself from costly repairs and lost time if you pay close attention to your equipment! Even the best lawn mowers can develop issues over time, whether it’s from irregular maintenance or regular wear and tear.

If you work with a professional mowing service, check in with them for any signs your mower is malfunctioning.

Keep an eye out for these symptoms of overfilled engine oil.


1. Hard or sputtering start

green lawnmower

One sure sign there’s too much oil is a “hard start.” 

This means either the lawn mower engine refuses to start at all, or it’ll briefly sputter then die.


2. White smoke from engine

If you do get your engine to start, you might notice some white smoke from the lawn mower.

In some cases, you’ll get blue smoke, which is caused by a difference in combustion temperatures.

Don’t panic – the smoke is coming from excess oil that’s leaked onto the outside of the engine. Since the oil is being heated up, it’s starting to smoke.


3. Engine starts then stalls

Lawnmower cutting bright green grass

Sometimes you can get your engine running – only for your lawn mower to start then die.

This can be especially frustrating as you’ve already started mowing, only for the engine to stall a few minutes later.


4. Clogged air filter

Too much oil sloshing around can eventually spill onto the air filter. The engine oil will cling to the mesh, which will attract dirt and other debris.

Eventually, the air filter becomes clogged, which creates other problems.

To fix this issue, besides draining the excess oil, you’ll also need to clean the lawn mower air filter. Paper filters can be thrown out and replaced, while foam filters can be washed with anti-grease dish soap.


5. Overheated engine

ride on lawnmower

If the engine housing feels excessively hot, that’s a clear sign of an overheated engine.

However, you don’t need to get close to the engine to check. You’ll likely be able to hear or even feel your engine struggling as you run the mower.


6. Oily or dirty spark plug

It’s important to check and clean your spark plug regularly – and especially after your mower’s been in storage for long, or if it’s stored in dusty conditions.

If you notice a greasy residue on the spark plug, that’s likely engine oil leaking out of an overfilled lawn mower.


7. Leaking oil in other areas

If there’s too much oil in your lawn mower, it can spill over into other areas.

For example, excess oil can get into the carburetor while you’re mowing at an angle or over uneven terrain.

Alternatively, the oil can flow towards the muffler or even the exhaust.

If there’s engine oil in places it shouldn’t be, there’s too much oil in the engine.


How to Remove Excess Oil from Mower Engine

 oil draining from a red lawnmower

So – you’ve identified the issue. Now, how to fix too much oil in the lawn mower?

For both push and ride-on mowers, the solution here is to drain excess oil from the engine. The container should only be filled to the line on the oil dipstick.

Start by ensuring your lawn mower is shut off and has cooled down. Remove the spark plug wire for additional preventive measures.

Check your owner’s manual to see if there are instructions on how to drain oil from the engine. 

Otherwise, there are a few methods you can try:

  • Tilt a push mower onto its side so oil flows out the fill hole
  • Find the drain plug or valve port (usually at the bottom of the oil pan or by the dipstick)
  • Loosen or remove the oil filter to let it drain
  • Use an oil extractor pump or evacuator (a tube inserted into the engine)

If you’re in a pinch, you can also use a turkey baster to remove small amounts of engine oil. However, do not reuse it for food afterwards – just toss it out and get a new one!

Whenever you’re draining the reservoir, there’s no need to remove all the oil from the engine. Keep an eye on the oil level so that you only drain enough oil that it reaches the fill line.

NOTE: If you’re tipping your push mower on its side, be sure the oil is flowing away from the combustion chamber.


How to Fix White or Blue Smoke from Lawn Mower

Shut off the engine immediately, and take out the spark plug for electric mowers. This minimises the risk of a fire hazard.

Check the other parts, such as the air filter, to make sure nothing else is causing the white smoke. If you’ve identified the problem as too much engine oil, then start the mower and let it run.

The oil will eventually burn off and the engine will stop smoking.

Alternatively, you can use some rags to wipe the oil off the engine before restarting.


How to Avoid Too Much Oil in Your Lawn Mower

Whenever you’re filling up the oil reservoir, take steps to make sure you don’t overfill! It’ll save you time, effort, and oil in the long run.

Read the owner’s manual beforehand so you know the oil requirements of your mower model. If you don’t have one, search your model online.

When adding oil, go slowly or only add a little at a time. Push mowers usually need around 3/4 of a quart, while larger ride-on models can go up to 2 quarts.

Use a dipstick while filling the engine. In most lawn mowers, this is a long, thin gauge under the oil cap that detects the amount of oil in the reservoir.

You can also buy a dipstick from your local hardware store.

The oil level in your engine should never exceed the “full” line. Check your engine regularly to ensure it always has sufficient oil to keep it running.

About Author

Jamie Donovan

Jamie is an Australian horticulturalist and landscape designer. He enjoys writing about landscape architecture, garden design and lifestyle topics.


About Author

Jamie Donovan

Jamie is an Australian horticulturalist and landscape designer. He enjoys writing about landscape architecture, garden design and lifestyle topics.