Learning how to change oil in Briggs and Stratton lawn mower is a simple task that every owner should master. Changing the oil in a Briggs & Stratton engine is a fundamental part of seasonal maintenance. It keeps your mower running smoothly, prevents costly repairs, and extends the engine’s life significantly. This guide will walk you through the entire process, from gathering tools to disposing of the old oil safely.
How To Change Oil In Briggs And Stratton Lawn Mower
This section provides the complete, step-by-step procedure. Before you start, ensure your mower is on a flat, level surface and the engine is cool to the touch. Working on a warm engine can help the oil drain more completely, but you should never work on a hot engine due to burn risks.
Tools And Materials You Will Need
Having everything ready before you begin makes the job quicker and cleaner. You likely already have most of these items in your garage.
- Fresh SAE 30 or 10W-30 motor oil (check your owner’s manual for the exact type and quantity)
- A new oil filter (if your model is equipped with one)
- An oil drain pan or old container
- A funnel
- Clean rags or paper towels
- A socket wrench or adjustable wrench
- A pair of gloves to keep your hands clean
- Cardboard or a mat to protect your work area
Step 1: Prepare Your Lawn Mower
Proper preparation is key to a mess-free oil change. Start by running the engine for a few minutes if it is cold. This warms the oil, allowing it to drain more freely and carry suspended debris with it. Then, turn off the engine and disconnect the spark plug wire. This critical safety step prevents the engine from accidentally starting while you are working.
Move the mower to your protected work area. Tilt the mower carefully, usually with the air filter and carburetor side facing up, to avoid fuel and oil leaks into those components. Some models have a dedicated drain plug, while others require tilting to drain from the dipstick tube.
Step 2: Drain The Old Engine Oil
Locate the drain plug on the bottom of the engine sump. It is typically a hexagonal bolt. Place your drain pan directly underneath it. Using your wrench, slowly loosen the plug. Once loose, unscrew it by hand but be prepared for the oil to flow quickly as you remove it completely.
If your mower does not have a drain plug, you will need to use the dipstick method. Carefully tilt the mower on its side so the dipstick tube is positioned over your drain pan. Slowly pull out the dipstick, allowing the oil to flow out the tube. Hold the mower steady until the oil stream slows to a drip. This method can be a bit messier, so take your time.
Let the oil drain for at least 5-10 minutes to ensure you get as much old oil out as possible. While it drains, inspect the old oil. If you see metallic flakes or the oil is extremely sludgy, it could indicate internal engine wear.
Step 3: Replace The Oil Filter (If Equipped)
Not all Briggs and Stratton engines have a replaceable oil filter. If yours does, you should change it with every oil change. After the oil has drained, locate the cylindrical oil filter on the side of the engine. Place your drain pan underneath it.
Use an oil filter wrench to turn the old filter counterclockwise until it loosens. Finish unscrewing it by hand. Before installing the new filter, dip your finger in the fresh new oil and lightly coat the rubber gasket on the top of the new filter. This ensures a good seal and makes future removal easier.
Screw the new filter on by hand until the gasket makes contact, then tighten it an additional three-quarter turn. Do not overtighten it with the wrench, as this can damage the gasket.
Step 4: Refill With Fresh Oil
Once the old oil is fully drained and any new filter is installed, return the mower to its level position. If you removed a drain plug, remember to clean it and screw it back in securely. Wipe away any spilled oil from the engine surface.
Locate the oil fill tube, which is where you check the dipstick. Insert your funnel. Slowly pour in the recommended type and amount of fresh oil. Your owner’s manual is the best source for the exact capacity, usually between 15 to 24 ounces. It is better to slightly underfill, check the level, and then add more than to overfill.
Step 5: Check The Oil Level
After adding most of the oil, wait a minute for it to settle in the crankcase. Remove the dipstick, wipe it clean with a rag, and fully reinsert it. Pull it out again to get an accurate reading. The oil should be between the “Full” and “Add” marks on the dipstick.
If the level is low, add a small amount of oil, wait, and recheck. Repeat until the level is correct. Be very careful not to overfill, as excess oil can cause smoking, hard starting, and even engine damage. If you do overfill, you may need to drain a small amount out using the drain plug or a fluid extraction pump.
Step 6: Final Checks And Cleanup
Once the oil level is perfect, securely replace the oil fill cap or dipstick. Reconnect the spark plug wire. Start the engine and let it run for about 30 seconds. This circulates the new oil throughout the engine. After shutting it off, wait another minute and check for any leaks around the drain plug or oil filter. Also, do a final check of the oil level on the dipstick, as it may have dropped slightly as the new filter filled.
Properly dispose of your old oil and filter. Never pour used oil on the ground or into drains. Most auto parts stores and recycling centers accept used motor oil and filters for free. Pour the oil from your drain pan into a sealed container for transport. Wipe down your mower and clean up your tools.
Choosing The Right Oil For Your Engine
Using the correct oil is as important as the change itself. Using the wrong type can lead to poor performance and increased wear.
Understanding Oil Viscosity
Viscosity refers to the oil’s thickness and its flow characteristics at different temperatures. Common recommendations for Briggs and Stratton engines include:
- SAE 30: A good choice for warmer climates and consistent summer use.
- 10W-30: A multi-viscosity oil that performs well in a wider temperature range, ideal if you use your mower in cooler spring and fall weather.
- Synthetic 5W-30: Offers excellent protection and can improve starting in cold conditions.
Always defer to your engine’s specific manual. The model number, located on the engine’s valve cover or blower housing, can be used to look up the exact specifications on the Briggs & Stratton website.
Oil Types: Conventional Vs. Synthetic
Most small engines do fine with high-quality conventional oil changed at regular intervals. However, synthetic oils provide superior protection against heat, oxidation, and deposit formation. They can be a worthwhile investment for commercial use or in extreme conditions. Some newer Briggs and Stratton engines even recommend synthetic blends. Check your manual to see if synthetic oil is allowed or recommended for your model.
When And How Often To Change The Oil
Sticking to a schedule is crucial. Old oil breaks down, loses its lubricating properties, and becomes contaminated with dirt and combustion byproducts.
Standard Maintenance Intervals
A general rule is to change the oil after the first 5 hours of operation on a new engine, and then every 50 hours of use or at least once per mowing season, whichever comes first. If you use your mower heavily or in dusty conditions, consider changing it more frequently, such as every 25-30 hours. An engine that sits with old oil over the winter can accumulate corrosive moisture.
Signs Your Mower Needs An Oil Change
Do not rely solely on the calendar. Watch for these indicators:
- The oil on the dipstick appears very dark black and dirty.
- The engine seems louder or runs rougher than usual.
- You notice increased exhaust smoke.
- It has been over a year since the last change, even with minimal use.
Common Mistakes To Avoid
Being aware of these pitfalls will help you complete the job correctly the first time.
Overfilling Or Underfilling The Crankcase
Both are problematic. Overfilling can cause aerated oil that fails to lubricate properly, leading to overheating. Underfilling means there is not enough oil to protect moving parts, causing rapid wear. Always check the dipstick multiple times during the refill process.
Using The Wrong Oil Or Filter
Do not just grab any oil from your shelf. Using automotive oil with friction modifiers or the wrong viscosity can harm small engines. Similarly, if your engine has a filter, use the exact replacement part number or a certified cross-reference. An ill-fitting filter can leak or bypass oil.
Improper Disposal Of Used Oil
This is an environmental hazard and often illegal. Used motor oil is a major pollutant. Always take it to a certified collection center. Many places that sell oil are required to accept used oil for recycling.
Seasonal Oil Change Considerations
Your approach might change slightly depending on the time of year.
Pre-Season Startup
If you changed the oil before winter storage, you should be good to go. If you did not, make an oil change your first task before starting the mower for the first time in spring. This removes any acidic condensation that formed over the winter.
End-Of-Season Winterization
One of the best things you can do for your mower’s longevity is to change the oil in the fall before you store it. This ensures that corrosive, contaminant-laden oil is not sitting in your engine all winter, potentially damaging internal seals and metal surfaces. After changing the oil, run the engine briefly to circulate the fresh, clean oil.
Frequently Asked Questions
How Do I Change The Oil In A Briggs And Stratton Lawn Mower Without A Drain Plug?
Many older or smaller models lack a drain plug. To change the oil, carefully tip the mower on its side with the air filter and carburetor facing up. Place a drain pan under the engine, remove the dipstick, and allow the oil to drain out through the dipstick tube. You can also use a fluid transfer pump to suck the old oil out through the fill tube, which is a very clean method.
What Is The Best Oil For A Briggs And Stratton Lawn Mower?
The best oil is the one specified in your owner’s manual. For most common residential engines in typical summer conditions, SAE 30 is recommended. For variable temperatures, 10W-30 is often suggested. For newer engines or extreme conditions, a synthetic blend or full synthetic like 5W-30 may be optimal. Always look for an oil that meets or exceeds the API service classification noted in your manual.
How Much Oil Does A Briggs And Stratton Lawn Mower Take?
Oil capacity varies by engine model. Common capacities range from 15 ounces (just under a pint) to 24 ounces (3 cups) or more. The safest way to know is to check your manual or the engine’s specification sheet. You can also find it by adding oil slowly after a complete drain until the dipstick reads full, keeping track of how much you poured in.
Can I Use Car Oil In My Lawn Mower Engine?
It depends. Some car oils, especially certain multi-viscosity grades like 10W-30, may be acceptable if they meet the required API service class (often SJ or later). However, you should avoid automotive oils labeled “Energy Conserving” as they contain friction modifiers that can cause clutch slippage in mowers with geared transmissions. When in doubt, use oil labeled for small engines.
How Often Should I Change The Oil Filter On My Mower?
If your Briggs and Stratton engine is equipped with a spin-on oil filter, it should be replaced every time you change the oil. This ensures all contaminants are removed and the filtration system is working at its best. Neglecting the filter allows dirty oil to circulate, diminishing the benefit of your fresh oil change.