April 1, 2017

How to tune up a riding lawn mower video

By Sears PartsDirect staff
How to tune up a riding lawn mower video.
How to tune up a riding lawn mower video.

Tune up the engine on your riding lawn mower at least once a year to keep it running efficiently. An engine tune-up includes changing the oil, oil filter, air filter, spark plug and fuel filter—this video walks you through the process so you can keep your engine performing at its best.

For additional repair help, including common symptoms and troubleshooting tips, step-by-step riding lawn mower and tractor repair guides and articles, check out our repair help section. In addition, find the riding mower parts you need to fix your mower.

Hi, Wayne here from Sears PartsDirect. Today we're going to tune up a riding lawn mower. Tuning up your mower engine every year helps your engine last longer and perform better. 

Supplies you may need

The first step is to gather the supplies for the tune-up. You need an oil filter, air filter, fuel filter, motor oil and spark plug—or 2 spark plugs if your engine has 2 cylinders. Many mowers have a sticker under that hood that lists part numbers for these supplies. Of course, you need a drain pan or container to catch the old oil. Use a container with a spout or a cover so you can carry the old oil to a collection facility after the oil change.

Also grab a strap wrench to loosen and tighten the oil filter. If you lost the oil drain tube that came with your mower (like I did), then you need one of those, too. A drain hose also helps you drain the oil directly into the oil pan without making a mess.

How to change the oil

Once you gather the supplies, run the mower for a few minutes in a well-ventilated area. This will warm the oil so it drains easily. Park the mower on a level surface. Set the parking brake and remove the ignition key. Lift the hood and disconnect the spark plug wire (or wires if your engine has more than one cylinder).

Now we're ready to get started with the oil change. To give you a better view, we’ve removed the hood. Remove the fastener from the lower right dash cover. Carefully slide the dash cover up slightly to release the locking tabs and remove the cover. Remove the oil drain valve cap and install the oil drain tube. Put an oil pan under the drain tube to catch the draining oil.

Push in and turn the drain valve counterclockwise to unlock it and then pull the drain valve outward to open. Remove the oil dipstick, taking care to keep debris out of the dipstick opening. Let the engine oil drain until it stops completely. Push the drain valve in and turn clockwise until the pin locks. Remove the oil drain tube and reinstall the drain valve cap. Reinstall the dash cover and secure it with the fastener.

Add new oil to the engine

The final step is to add new oil. Because some oil might remain in the mower after you drain it, you might end up adding less than the amount specified in the owner’s manual. To avoid overfilling, follow these steps.

  • Pour clean oil through the dipstick tube, stopping several ounces before the full amount specified in the owner’s manual.

  • Wait a minute for the oil to settle in the engine sump.

  • To check the oil level, wipe the dipstick with a shop rag and push the dipstick all the way into the dipstick opening and lock it.

  • Then unlock it and pull it out. If the oil doesn’t reach the top of the full mark on the dipstick, add a little more oil, wait a minute and check again.

  • Repeat until oil reaches the top of the full mark.

  • Reinsert the dipstick.

How to change the air filter

Next, we'll change the air filter. This engine uses a foam pre-filter and air filter, so replace both when you tune up the engine. Turn the air filter cover retaining knobs counterclockwise to release and pull off the air filter cover.

Release the air filter from the intake tube and pull out the filter. Slide the new pre-filter over the new air filter and attach to the intake tube. Slide the filter into the housing and reinstall the air filter cover. Turn the retaining knobs clockwise to lock the cover in place.

How to replace the spark plug

Now it's time to replace the spark plug. Use a spark plug wrench to remove the spark plug from the engine cylinder. Using a gap tool, set the gap on the new spark plug to the gap specified in your owner’s manual. For this engine, the gap is .03 inches. Thread the new spark plug into the engine and tighten it with the spark plug wrench. Don’t reconnect the spark plug wire yet.

How to change the fuel filter

The last item we'll replace on this engine is the fuel filter. Use two pinch-off pliers to clamp the fuel line on both sides of the fuel filter. Place a shop rag under the filter to catch fuel. Release the hose clamps and pull the fuel line off each side of the fuel filter. Remove the filter and wipe up any spills.

Connect the fuel line to each side of the new filter using the pliers. Release the hose pinch-off pliers from each side of the fuel filter. Reinstall the lower left dash, and tighten it with the fastener. Reconnect the spark plug wire and lower the mower hood.

Re-check the oil level

Now that we have everything installed, we'll start the engine and re-check the oil level. In a well-ventilated area, we'll run the engine for a few minutes to move the oil through the engine, and then shut it off and check the oil level. Allow a minute for the oil to settle in the engine sump. Lift the mower hood and check the oil level one more time.

Add oil if needed to hit the full mark on the dipstick. Now you can dust off your hands and pat yourself on the back for taking such good care of your engine. The engine will pay you back with years of efficient and dependable service.

I hope this video helped you out today. You can find links to the parts and products we talked about in the video description below. Check out our other videos here on the Sears PartsDirect YouTube channel. Subscribe, and we’ll let you know when we post new videos.

Symptoms common to all riding mowers & tractors

Choose a symptom to see related riding mower and lawn tractor repairs.

Main causes: worn or broken ground drive belt, bad seat switch, transaxle freewheel control engaged, transaxle failure, dirty carburetor
Main causes: dead battery, stale fuel, bad starter solenoid, ignition system problem, bad ignition interlock switch, clogged carburetor
Main causes: damaged cutting blade, worn deck pulley, damaged mandrel pulley, loose fasteners on mower deck components
Main causes: engine overfilled with oil, leaky head gasket or sump gasket, damaged carburetor seals, cracked fuel pump, broken fuel line
Main causes: punctured tire or inner tube, leaky valve stem, damaged wheel rim
Main causes: unlevel mower deck, dull or damaged cutting blades, worn mandrel pulleys, bent mower deck, engine needs tune up
Main causes: damaged tie rods, bent or worn wheel spindle, worn front axle, damaged sector gear assembly
Main causes: worn or broken blade belt, broken belt idler pulley, blade clutch cable failure, bad PTO switch, damaged mandrel pulleys
Main causes: shift lever needs adjustment, neutral control needs adjustment

Repair guides common to all riding mowers & tractors

These step-by-step repair guides will help you safely fix what’s broken on your riding mower or lawn tractor.

How to replace the starter motor on a riding lawn mower

If you hear the solenoid click but don’t hear the starter motor spin when you turn the key, follow these steps to replace it.

Repair difficulty
Time required
 30 minutes or less
January 1, 2015
By Lyle Weischwill
How to replace a riding lawn mower spark plug

If the engine is hard to start or if the spark plug electrode is burnt or cracked, take 15 minutes to replace it.

Repair difficulty
Time required
 15 minutes or less
January 1, 2015
By Lyle Weischwill
How to replace a riding lawn mower carburetor

If the engine of your lawn tractor surges or is hard to start, the carburetor could be the problem. Follow these steps to install a new one.

Repair difficulty
Time required
 45 minutes or less

Articles and videos common to all riding mowers & tractors

Use the advice and tips in these articles and videos to get the most out of your riding mower or lawn tractor.

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