Guide to Lawn Mower Oil

Spring Lawn & Garden Equipment Maintenance 101
October 7, 2022

All gas-powered motors need oil to operate smoothly and efficiently, regardless of size. Lawn mower engines are no exception. Running your lawn mower with deteriorated oil or low oil levels can lead to reduced performance, costly repairs and even complete breakdowns.

Conducting the appropriate equipment maintenance is essential for a healthy-looking lawn and extended mower life. One of the first steps for proper mower care is understanding your equipment’s engine oil requirements.


Why Lawn Mower Oil Is Important

Knowing the engine type is critical for understanding how your lawn equipment works. With a few exceptions, most gas-powered mowers use 4-cycle engines, meaning they have two tanks — one for fuel and one for oil. Devices like hedge trimmers, edgers and tillers typically run on 2-cycle motors, with a single tank holding a premixture of gasoline and oil.

Like all 4-cycle internal combustion engines, lawn mower motors require oil. Even the most basic lawn mower engines have various moving parts and components designed to perform in high temperatures and at high operating speeds. Without the oil’s cooling and lubricating properties, the engine would overheat and cease to function, often leading to permanent damage or ruin.


Choosing the Right Oil Type for Your Lawn Mower

The same standard engine oil used in cars and trucks works just as well in your lawn mower as the more expensive oils blended explicitly for small engines. Different types of oil grades are more effective in particular environments and temperatures. Your owner’s manual will tell you the specific oil type your equipment can use. 

Some of the most common lawn mower oil options for 4-cycle engines include:

  • SAE 30: This is the most popular grade of oil for small engines and is especially effective in warmer temperatures.
  • SAE 10W-30: Although this option may increase oil consumption, it offers solid protection for a diverse temperature range while improving cold-weather starting. 
  • Synthetic SAE 5W-30: This grade offers optimal protection at all operating temperatures while providing improved starting times with less oil consumption.
  • SAE 5W-30: This type is highly effective for cold temperatures.
  • 15W-50: This grade is ideal for continuous operations like commercial lawn mowing and works well in varying temperatures.

If your mower has a 2-cycle engine, your operations manual will indicate the proper mixing formulas for oil and gas. These engine designs are becoming increasingly less common because of global emissions regulations.


Using Synthetic Oil in Your Lawn Mower

Because synthetic oil is superior to the lubricants found in crude oil, your engine might perform better and last longer if you fill it with synthetic. Manufacturers blend synthetic oil with artificial ingredients and compounds to deliver the performance and protection that some natural oils cannot offer. However, you still need to change your oil at the required intervals even though you use an upgraded blend.


How to Check Your Lawn Mower’s Oil Level

Checking your oil before each mowing session and topping it off when needed ensures you always maintain the required level. Complete the following steps for an accurate oil check:

  1. Remove the dipstick from the oil reservoir and clean it thoroughly.
  2. Return the dipstick to the reservoir, so it fits securely.
  3. Remove the dipstick and find the oil level.
  4. Ensure the level is between the two arrow indicators on the end of the dipstick.
  5. Return the dipstick to the reservoir and secure the cap tightly.

It’s also critical to remember not to overfill your reservoir, as too much oil can damage the seals, gasket and combustion chamber, causing the engine to malfunction.


Changing the Oil in Your Lawn Mower

Changing the oil in your mower at the recommended intervals will keep your engine healthy and ensure peak performance. Generally, owners should change the oil in a walk-behind mower with a 4-cycle engine once per season or every 50 hours of mow time. Riding mowers typically require an oil change once per season or every 100 hours of run time.

A typical oil change for a push mower or riding mower involves the following steps:

  1. Determine the draining method: Several options exist for draining the old oil from your mower, including from the top of the reservoir, with the plug at the bottom of the engine on the undercarriage or with an extractor tool.
  2. Warm up the oil: Running your mower for several minutes before changing the oil helps remove dirt and debris from the engine compartment.
  3. Shut down the engine and disconnect the spark plug wire: This step ensures the mower will not accidentally start while you maintain it.
  4. Seal the gas tank: If you’re not using an extractor tool, remove the gas cap and cover the opening with a plastic bag. Tighten the cap over the plastic bag.
  5. Empty the old oil: Pour the oil into the appropriate container for safe recycling.
  6. Refill with clean oil: Choose the proper grade and correct amount based on your manufacturer’s recommendations.

Checking the mower’s air filter for cleanliness when performing an oil change can help streamline your maintenance checklist and ensure your mower stays in top operating condition. 


Choose Hot Shot’s Secret Additives for Your Lawn Mower

Hot Shot’s Secret offers several high-quality additives to increase the performance of your lawn mower’s small engine. Our FR3 Friction Reducer improves the wear reduction and lubricating properties of your engine’s oil, allowing you to gain up to a 5% increase in mileage and horsepower. Our Gasoline Extreme deep cleans your mower’s fuel injectors and restores optimal flow by removing valve deposits and lubricating your fuel system’s critical components.

To learn more about how our additives can benefit your lawn care equipment, connect with our team online or call 800-341-6516 today.