Having a bit of trouble getting your mower started? Got oil or a bunch of carbon buildup on your spark plugs? You could have a lawn mower with oil in the cylinder.
Where diagnosing your problems can get a little complicated depends on the type of lawn mower you have. Since two-stroke engines run on a fuel and oil mix they will have different reasons for excess oil in the cylinder compared to four-stroke lawn mowers.
But, in either case, you’ll want to figure out what is causing oil to get into the combustion chamber and take care of it before it leads to any serious issues.
Why is There Oil in My Cylinder?
The reason why your lawn mower has oil in the cylinder largely depends on the type of engine it has. I’ll break down the potential causes for two-stroke vs four-stroke mowers separately below.
When it comes to two-stroke engines, there is actually always a bit of oil residue in the cylinder and usually on the spark plug. The mixture of oil and fuel that these types of engines burn is meant to leave a bit of oil behind as a lubricant. But, If you’ve noticed a bunch of excess oil in the cylinder of your two-stroke mower there might be a problem.
This is usually caused by a “rich” mixture meaning that too much oil has been added to the fuel. It can be kind of tricky to measure the exact amount of oil needed each time you put gas in your mower, but it is really important to get it right.
If you’re sure you have it right, you could have a spark plug that isn’t firing reliably. You’ll probably hear the mower running roughly if this is the case, but it would mean the fuel isn’t being completely burned and is leaving oil behind.
With four-stroke engines, the main reasons for lawn mower oil in the cylinder are: tilting the lawn mower incorrectly, overfilling the oil reservoir, oil leaking into the gas tank, and damaged engine parts. The best way to tell if your lawn mower has oil getting into the cylinder is to check the spark plug. On a four-stroke mower, the spark plug should never be oily. Another common sign of oil getting to where it shouldn’t be and burning off is a lawn mower blowing white or blue smoke.
The most common reason for oil in the cylinder listed above is probably tilting your lawn mower the wrong way. Easily avoidable, very silly, but easy to do. I’ve been known to put gas in the mower oil tank when not paying attention, so I feel your pain! Following that is adding too much oil. Like two-stroke mowers, too much oil, or oil mixing with gas can leave your mower with extra oil in the cylinder. If neither of those is the case, you might be looking at a number of more complicated mechanical issues including bad gaskets or seals in your engine.
How to Get Oil Out of Lawn Mower Engine Cylinders? (5 Ideas)
Well, you have too much oil in the cylinder of your lawn mower and you need to get it out of there. Let’s talk about some of the best ways to do so and when each approach should be used.
Let it Sit
In many cases with four-stroke engines, just letting your lawn mower sit could be your best bet. Gravity can do most of the work for you and the oil should seep back into the crankcase where it should be. This is the best approach to start with. But if you let the mower sit for a few hours and the oil is still there, you’ll want to try one of these other methods too. In either case, you should consider how the oil got there in the first place and try to remedy the problem so that it won’t happen again.
Wipe it Out
Accessing the cylinder from your spark plug well can be a good way to clean up any sitting oil. Since you don’t have a ton of room to work with, you’ll probably want to use a paper towel and a thin object like a marker. Just be sure you don’t use anything that could scratch up the inside of the cylinder. Then, wrap the paper towel around the object in a thin cylinder and insert it into the well. Push it around a little bit before removing it and repeat as necessary until most of the oil is soaked up. You can do this on two or four-stroke mowers.
Burn it Off
Believe it or not, starting your lawn mower up, wheeling it outside, and letting it billow smoke can be a good solution. However, you should only do this in a couple of scenarios. The first would be after letting your mower sit for a while to drain off most of the oil. You could also use this method if there is only a small amount of oil in your cylinder to begin with. This could be the case if you have a small amount of a rich fuel mixture left in your two-stroke mower, or if you’ve just changed the oil or corrected the oil level in your four-stroke mower. Burning off oil here and there won’t damage the engine immediately, you just don’t want to run extra oil in your mower consistently.
Grab a Turkey Baster
This might seem a little strange, but using a kitchen baster can work well to draw oil out of a cylinder. The idea here is pretty self-explanatory, simply follow the same process as you would when wiping out the cylinder. One thing to note is that you may need to attach a bit of thin plastic tubing to the end of the baster to reach down far enough to get at the sitting oil. After you’ve sucked out what you can, running the engine to burn the rest off may work well.
Tip the Mower
If nothing else works, tipping the mower over with the help of a friend could do the trick. Just be sure you do it the correct way. You will want to make sure that the spark plug well is facing down because that’s where the oil will drain from. Also, either make sure the air filter is facing up or remove the air filter before tilting the mower. If you don’t do this you’ll end up having to replace it because it will probably get covered in oil.