How It Works: Lawn Mower


Lawn mower won’t start or won’t stay running? This video provides information on how a lawn mower works and offers troubleshooting tips to assist you in diagnosing and repair.

Here is a list of the most commonly replaced parts associated with each lawn mower symptom:

Lawn mower won’t start: spark plug, carburetor, start switch, fuel pump
Lawn mower engine stops after a few seconds: carburetor, gas cap, spark plug
Lawn mower battery keeps draining: battery, charger, alternator, voltage regulator
Lawn mower leaks gas: carburetor bowl gasket, float needle, primer bulb, fuel shut-off solenoid
Lawn mower wheels won’t turn: v-belt, drive pulley, wheel assembly, transmission
Lawn mower is hard to start: carburetor, primer bulb, carburetor, spark plug, fuel pump

All of the information provided in this lawn mower troubleshooting video is applicable to the following brands: Craftsman, Honda, Huskee, John Deere, MTD, Murray, Snapper, Toro, Troy-Bilt.

RepairClinic has millions of replacement parts for appliances, lawn equipment, power tools, and heating & cooling equipment including washers, dryers, dishwashers, refrigerators, lawn mowers, snowblowers, furnaces, and air conditioners. Our customer care team is available to help by phone or live chat, seven days a week: 1-800-269-2609. We guarantee the fastest shipping possible—all in-stock parts ship the same business day. Return any part for any reason with our generous 365-day return policy.

In addition to providing replacement parts, offers free online troubleshooting information and DIY repair videos. Use our website to choose from a series of problems to discover the likely causes and the correct replacement part(s) for your particular model. Once you’ve determined the solution, our expertly-produced video tutorials will guide you through every step of the repair.

At RepairClinic, we make fixing things easy!
1Maintenance tips for your lawn mower
Maintenance tips for your lawn mower
Your lawn mower is likely the most frequently used piece of outdoor power equipment that you own. Proper maintenance is extremely important to maximizing efficiency, reducing emissions, preventing costly repairs and extending the life of your lawn mower.
2Always have a clean air filter in place.
Always have a clean air filter in place.
The air filter has the important job of preventing dirt, dust and debris from entering the carburetor and engine. It should be cleaned or changed every 25 hours of engine operation or once per mowing season. Pleated, paper air filters must be replaced. Foam air filters can be cleaned with hot water and a small amount of detergent and then left to air dry before being saturated with new engine oil and reinstalled.
3Check and changing the oil regularly.
Check and changing the oil regularly.
Every eight hours of use, check the condition and level of the oil. Fresh oil is golden or amber in color. As it ages, it will darken. Change the oil every 50 hours of use (generally once per season). Always use the oil recommended by the manufacturer for that model.
4Use a clean fuel filter.
Use a clean fuel filter.
Ensure that a clean fuel filter is in place and replace it if necessary. We do not recommend cleaning the fuel filter since it is delicate and can be easily torn during the cleaning process.
5Check tire pressure.
Check tire pressure.
If your mower has pneumatic tires, periodically use a tire pressure gauge to ensure consistent tire pressure. Tires with varying pressures will result in uneven or poor cutting.
Spray a degreaser on oil stains. Allow the degreaser to sit for 10-15 minutes before wiping with a clean cloth. Rinse with a hose.
7Check the blade and replace, if needed.
Check the blade and replace, if needed.
Look for bends, dents and other damage to the blade. To prevent risk of injury, the blade should be replaced right away if any damage is found. Also, a sharp blade is important to a proper cut. Dull blades tear the grass, rather than cut cleanly. A blade should be sharpened every season and replaced every one to three years, depending on usage. A universal blade is not recommended, due to safety issues related to the metal used and problems with proper mounting. Only the blade recommended by the manufacturer should be used. Enter your lawn mower model number to find the blade(s) recommended for your model.
8For convenience, pick up a tune-up kit.
For convenience, pick up a tune-up kit.
A tune-up kit packed with essentials including an air filter, spark plug, oil and more as needed for your engine will take the guess work and hassle out of purchasing the correct parts for a specific engine. Find the tune-up kit for your lawn mower by entering the model number.
9Add fuel stabilizer to fresh fuel.
Add fuel stabilizer to fresh fuel.
This will keep fuel fresher longer. Follow the owner’s manual for instructions on leaving fuel in the engine during storage, as this varies by manufacturer.
10Winterize your lawn mower
Winterize your lawn mower
? Clean the fuel cap at the end of the mowing season. Fuel caps have vent holes to allow air into the fuel tank. Use a paintbrush to brush away particles and buildup on the fuel cap. Before closing the fuel cap, inspect for blockage and replace it if there’s blockage. • Replace the spark plug. It’s a good idea to replace a spark plug once per season, even if it appears to be working fine. Over time, a spark plug’s performance will degrade due to carbon build-up and a weakened electrode. This dramatically increases emissions, reduces engine performance and increases fuel consumption. Only the engine manufacturer’s recommended spark plug should be used, as using an alternative can cause damage to the engine. • Spray lubricant on any bare metal undercarriage parts to prevent rusting. Check the mower owner’s manual for the recommended way to handle oil replacement. Most small engine repair shops and auto parts stores have a free recycling program for used oil.

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