Lawn Mower Lubrication

Your lawnmower works long hours in one of the dustiest, dirtiest environments you can imagine. Like any other internal combustion engine, it relies on oil in the engine crankcase to keep it all lubricated.

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Your lawnmower works long hours in one of the dustiest, dirtiest environments you can imagine. Like any other internal combustion engine, it relies on oil in the engine crankcase to keep it all lubricated.

While it may be easy to forget about your lawn mower lubrication, it is a terrible idea. All of the dirt and contaminants in the environment around the mower can gradually buildup a sludge and carbon on the bearings and other components and will eventually wear down your engine. You never neglect performing oil changes in your car for that very same reason; so why would you do that to your lawn mower lubrication?

How Do You Select the Best Motor Oil for Your Mower?

The best news is, you don’t need to run a special oil in your lawn mover—ordinary automotive engine oil will do the trick. (NOTE: This does NOT apply to weed-whackers or other lawn care equipment that use a two-cycle engine and needs a premixed oil & gas mixture. They require a specially-formulated two-cycle oil.)

For the bulk of mowers, a straight 30W or a multi-grade engine oil such as 10W-30 will work well. If you live in an very cold climate, you might consider running a thinner viscosity multi-grade motor oil such as 5W-30. This thinner weight oil can circulate through the engine more quickly in cold weather, whereas a thicker oil might become more viscous in extreme cold.

Make sure to choose an oil that is good quality with a SF, SG, SH, or SJ rating and that it has a detergent in the engine oil. There is no need to use any special kind of additives, using straight oil will be good.


Using Synthetic Oil in My Lawn Mower Engine

The answer to that one is yes, yes, yes. You can reap the same benefits as an automotive engine using synthetic oil just in your small engine.

Synthetic oil has greater stability across a wide range of temperatures and will not thin out in extreme heat or thicken in extreme cold weather like conventional oil. It will offer better, longer engine protection and can go for longer intervals between oil changes.

Still, considering how dirty a mower’s working environment is, it’s recommended to change the oil at the beginning of each mowing season even if you use a synthetic.

How to Change the Oil in Your Lawn Mower

This is a pretty simple task, since single-piston lawn mowers generally don’t have oil filters nor a drain plug. Let the engine run for about 60 seconds to recirculate any sludge and dirt that might be in the oil (rather than leaving it in the bottom of the crankcase). Tip the mower over on its side and remove the filler plug and dipstick.

Let the oil run out until the crankcase is empty, then refill. Be sure to drain it into an oil-safe drain pan, and don’t let any used oil drain onto the ground. Dispose of the old oil properly.


Most one-cylinder mower engines will need about a quart of oil. Check the oil fill level with the dipstick. You are ready to go once the oil is up to the fill line with a crankcase full of the right oil for your mower. While you are in there you may want to change out your spark plug. Now it’s time to cut those green blades of grass!

Select your Lawn Mower Oil