Lawn Mower Maintenance: Tune-Ups and Walk-Behind Mower Parts

General Walk-Behind Lawn Mower Maintenance

It's important to perform regular lawn mower maintenance to ensure your machine is running well when you need it.  Follow these simple steps for replacing walk-behind mower parts and performing push mower maintenance to help extend the life of your mower.

Depending on your model, the instructions below may vary slightly. If while performing lawn mower maintenance you find there are any safety features missing or broken, you should take the mower to an Authorized Service Center. For more detailed instructional videos on specific repairs, please see our how-to and video libraries. Also, have a pad and paper handy so you can note any walk-behind mower parts you need to order. It's important to purchase the Original Equipment Manufacturer's mower parts so your machine continues to run smoothly and safely. Other walk-behind mower parts can wear out more quickly or cause damage to the mower or its operator.



Step 1: Set up your push mower for safe lawn mower maintenance

To begin, place the mower on a flat, level surface.

Then, disconnect the spark plug wire to avoid unintentional starting.


Step 2: Inspect the spark plug for wear and tear

One of the walk-behind mower parts you may need to replace is your spark plug. Check it every 100 hours or prior to storing and pay attention to the numbers on the old plug so you can order the right replacement. Damaged or worn plugs can decrease fuel efficiency, power output and increase carbon build-up. Plus, using a spark plug with the wrong specifications can damage your engine.


Step 3: Change your lawn mower's oil

You should change your lawn mower's oil every 50 hours and prior to storing the machine in the fall. It is important to change your engine oil because heat and friction break down the oils' ability to lubricate moving parts and removes worn particles from the engine. If you don't change your lawn mower's oil, you could cause the engine to wear prematurely. To drain the oil, use one of three methods:

The drain plug, if your push mower has this feature.

The Arnold Siphon Pump for mowers without a drain plug.

Tilt the mower and drain the oil through the dipstick tube if the above options aren't available.  When you change lawn motor oil with this method, ALWAYS tilt the mower so the air filter is facing up.


Step 4: Refill the oil during your lawn mower maintenance

Refer to your operator's manual for the type and amount of oil needed to refill. Remember, overfilling can be as harmful as under-filling.


Step 5: Clean or replace the air filter

The air filter should be replaced during lawn mower maintenance performed after every 100 hours of use. As dirt accumulates in air filters, it can choke out the engine, robbing it of power and causing abnormal fuel use. Dispose of the dirty air filter and add a new air filter to the list of walk-behind mower parts you need to order. You may want to order commonly replaced walk-behind mower parts like this ahead of time so you can have them on hand when you need them.

If your mower is equipped with a pre-filter, clean it with liquid detergent and water. Thoroughly dry it before reinstalling.  Never operate your mower without a proper fitting air filter to avoid dirt or grass in your engine.


Step 6: Add Fuel stabilizer for maximum performance

Difficulty starting the engine is a common problem often caused by faulty fuel. With today's emissions standards, small, air cooled engines cannot tolerate untreated fuel that has been sitting in a gas can for over 30 days or fuel with more than 10% ethanol. To prevent these problems, add a fuel stabilizer to your gas can every time you refill it. Fuel stabilizers help to keep fuel combustibility levels up to specifications so you can use it for more than 30 days.  


Step 7: Sharpen worn mower blades and change when chipped or bent

Dull or worn mower blades are harmful to your lawn. They tear the blades of grass, making it susceptible to disease and causing it to appear brown. If the mower blade is chipped, bent or damaged - replace it. Running a mower with a bent blade can cause excess vibration and unsafe mowing conditions. Replacement mower blades, the blade removal tool and the balancer/sharpener kit are available through our Part Finder.


Step 8: Inspect the drive belt for wear

If your mower is self-propelled, check the self-propel drive belt for wear or damage and replace it if necessary. If you need to replace it, write down the part number and order genuine factory lawn mower belts from MTD Parts. These walk-behind mower parts are designed specifically for your machine's pulley system and torque needs. Non-original belts may not set in the pulley properly or they may stretch, causing premature wear and replacement. It's also a good idea to clean any debris build-up from the underside of the deck as you perform lawn mower maintenance.


Step 9: Take a look at the trail shield at the rear of the mower

Check the trail shield at the back of the mower for wear or damage during lawn mower maintenance. If this or any other safety feature is not functioning properly, immediately take your mower to an authorized service center. A service locator can be found on your mowers brand's website.


Step 10: Look for holes or tears in the grass bag

Check your lawn mower's grass catcher for wear or damage. If there are holes or tears, operating the product could be very dangerous.


Step 11: Clear the discharge chute of debris

Remove grass or debris from the discharge chute and mulching plug.


Step 12: Examine the drive wheels

Check your drive wheels for excessive wear or damage.


Step 13: Inspect the cables, handle bars and operator presence bar

Inspect the cables for the drive, operator presence bar, speed control and throttle. Look for fraying at the ends or kinks and possible cracks where the handle bars fold down for storage. Any needed service should be performed by an authorized service center.


Step 14: Replace any necessary walk-behind mower parts

Once all of the necessary parts have been replaced, check to make sure all fasteners are tight.


Step 15: Clean up spilled oil and fuel

Wipe up any fuel or oil spilled during the repair and reconnect the spark plug wire.


Step 16: Fill the mower with fuel

Last, fill the fuel tank with FRESH fuel and start the mower. Try to purchase fuel with the lowest amount of ethanol possible as ethanol attracts water and water corrupts an engines fuel system. Don't forget to add fuel stabilizer!

Be aware, sometimes after being tilted on its side the engine will smoke on startup. This should stop after a short period of run time. Now, you are good to go!