Step-by-Step Guide to Changing Oil in Your Briggs & Stratton Lawn Mower

Why Regular Oil Changes Matter

Oil keeps your Briggs & Stratton engine running smoothly and protects all the moving parts inside. Over time, oil gets dirty from dust, debris, and engine wear. It also breaks down and loses its ability to protect your engine. Changing it regularly helps your mower last longer, run better, and start more reliably when you need it.

Most Briggs & Stratton engines need an oil change every 50 hours of use, or at least once a year if you use your mower less often. If you mow frequently during the season, you may need to change the oil more than once. Checking your mower's manual will tell you the exact schedule for your specific model. Skipping oil changes can lead to engine damage that costs far more to fix than the price of regular maintenance.

What You'll Need

Before you start, gather all the items you'll need so you don't have to stop midway through the job. Having everything ready makes the process go smoothly and helps you stay organized.

• New oil (check your mower's manual for the right type and amount—usually SAE 30 or 10W-30)
• An oil drain pan or container to catch the old oil
• A wrench or socket set to fit your drain plug
• A new oil filter (if your model has one)
• Rags or paper towels for cleaning
• A funnel to pour oil safely
• Safety glasses to protect your eyes
• Work gloves to keep your hands clean

You may already have most of these items at home. If you need to buy anything, auto parts stores and hardware stores carry everything on this list at low cost. Don't skip the safety glasses—old oil can splash, and you want to protect your eyes.

Prepare Your Mower

Start by letting your mower cool down for 10 to 15 minutes if you've been using it recently. Warm oil drains better and faster than cold oil, but oil that's too hot can burn your skin. Find a safe, level spot in your yard or garage where you can work without the mower rolling or tipping. Make sure the ground is flat and stable.

Turn off the engine and let it sit for those 10 to 15 minutes. Once it's cooled slightly, disconnect the spark plug wire from the spark plug. This is an important safety step that prevents the engine from accidentally starting while you're working on it. You can simply pull the wire off the plug—it will come free easily. Now you're ready to begin draining the old oil.

Drain the Old Oil

Locate the drain plug on the bottom or side of your engine. On most Briggs & Stratton mowers, it's on the underside of the engine block. Position your drain pan directly underneath the drain plug to catch all the old oil. If you don't catch it, the oil will spill on your yard or garage floor and create a mess.

Use your wrench to loosen the drain plug by turning it counterclockwise—remember "lefty loosey, righty tighty." Once it's loose enough to grip, carefully unscrew it the rest of the way by hand. Be careful because the oil may still be warm. Let the old oil drain completely into the pan. This may take several minutes, so be patient and let gravity do the work. Once the oil stops dripping, you can move on to the next step.

Replace the Oil Filter (If Equipped)

Not all Briggs & Stratton models have an oil filter, so check your manual to see if yours does. If your mower does have a filter, you'll see it mounted on the side of the engine—it looks like a small metal cylinder. If your model doesn't have a filter, skip this section and move to the next step.

If you do have a filter, use an oil filter wrench to turn it counterclockwise until it comes loose. Once it's loose, you can unscrew it by hand. Be careful because some oil may still be inside the filter. Wipe the filter mounting surface clean with a rag to remove any dirt or old oil residue. Take your new filter and apply a thin layer of new oil to the rubber gasket (the ring around the top). This helps create a good seal. Screw the new filter on by hand until the gasket touches the mounting surface, then turn it an additional three-quarters of a turn. Don't use a wrench for this—hand-tight is correct.

Install the Drain Plug

Take the drain plug you removed and wipe it clean with a rag to remove any old oil or debris stuck to it. This helps you see if the plug is in good condition and ensures a clean seal when you reinstall it. Look at the plug to make sure the threads aren't damaged.

Screw the drain plug back into the opening by hand first. Once it's started and sitting flush, use your wrench to tighten it. Turn it clockwise until it's snug—firm enough that it won't leak, but don't over-tighten it. Over-tightening can strip the threads or crack the plug. If you're unsure how tight is right, aim for "snug" rather than "as tight as you can make it."

Add New Oil

Place your funnel in the oil fill opening on top of the engine. This opening is usually marked with an oil can symbol or the word "OIL." Slowly and carefully pour the new oil through the funnel. Check your mower's manual for the correct amount—most small Briggs & Stratton engines take between 1 and 2 quarts. Pour slowly to avoid splashing or overfilling.

After you've poured in the oil, wait about a minute for it to settle and flow down into the engine. Then use the dipstick to check the level. The dipstick is usually attached to the oil cap or located nearby. Pull it out, wipe it clean with a rag, reinsert it fully, and pull it out again to check the level. The oil should reach the full mark on the stick. If it's low, add a little more oil and check again. Getting the level right is important—too little oil can damage the engine, and too much can cause problems too.

Finish Up and Test

Replace the oil cap and make sure it's tight. Wipe up any oil spills with a rag so your work area stays clean and safe. Reconnect the spark plug wire to the spark plug by pushing it firmly back onto the plug until you hear or feel it click into place.

Now start your mower and let it run for about a minute. This circulates the new oil throughout the engine and helps it settle into all the right places. Turn off the engine and wait a few minutes for the oil to settle again. Check the oil level one more time with the dipstick. Top off if necessary to reach the full mark. Once everything looks good, you're done with the oil change.

Dispose of Old Oil Properly

Never pour old oil down the drain, into the ground, or into the trash. Used oil is harmful to the environment and can contaminate water supplies. Proper disposal is important and usually easy to do.

Take your container of old oil to a recycling center, auto parts store, or service station that collects used oil. Many of these places take used oil for free, and some may even pay you a small amount. Call ahead to confirm they accept oil and ask about their hours. This small step protects the environment and is the responsible way to handle old motor oil.

Key Takeaways

• Change your Briggs & Stratton mower's oil every 50 hours of use or at least once a year.
• Always let the engine cool for 10 to 15 minutes before draining oil to avoid burns.
• Disconnect the spark plug wire before starting work to prevent accidental engine starting.
• Drain old oil completely and replace the oil filter if your model has one.
• Fill with the correct type and amount of new oil as specified in your manual.
• Always dispose of old oil at a recycling center or auto parts store, never down the drain.
• Check the oil level with the dipstick after filling and after running the engine.

Frequently Asked Questions

How often should I change the oil in my Briggs & Stratton mower?

Most Briggs & Stratton engines need an oil change every 50 hours of use. If you use your mower less frequently, change the oil at least once a year, typically at the start of the mowing season. Check your specific mower's manual for the exact recommendation, as some models may differ slightly. Keeping track of your mowing hours helps you stay on schedule.

What type of oil should I use in my Briggs & Stratton engine?

The correct oil type depends on your specific model and where you live. Most Briggs & Stratton small engines use either SAE 30 or 10W-30 oil. Your mower's manual will clearly state which type to use. In colder climates, 10W-30 is often recommended because it flows better in low temperatures. Always follow your manual's recommendation rather than guessing, as using the wrong oil can damage your engine.

Can I change the oil without an oil filter wrench?

If your mower has an oil filter and you don't have a filter wrench, you can try using a rubber strap wrench or even wrap an old cloth around the filter for grip. However, an oil filter wrench is inexpensive and makes the job much easier. They're available at any auto parts store for just a few dollars. If the filter is too tight to remove by hand, a proper wrench is your best option to avoid damaging the filter or the mounting surface.

What should I do if I accidentally overfill the oil?

If you add too much oil, the engine may smoke, run poorly, or leak oil. To fix this, let the engine cool, then use the dipstick to check the level. If it's above the full mark, you'll need to drain some oil out. Place your drain pan underneath, loosen the drain plug slightly, and let a small amount of oil drip out until the level is correct. Then tighten the plug again. It's better to add oil gradually and check often than to overfill and have to drain some out.