Push mowers can have many possible problems causing them to not work properly. Most of these problems can be resolved with simple maintenance practices. Understanding these common issues helps make maintenance easier to handle. Remember to always disconnect the spark plug wire before conducting any type of maintenance to avoid the mower starting by accident.
Mower Doesn't Start
Check the spark plug and its wires for dirt or damage and clean them if necessary with a wire brush. Check the battery's voltage by putting the battery on a multimeter. Check the battery cables for corrosion or dirt and clean with a wire brush. Examine the level of the fuel and oil. While doing this, look at the coloring of the fuel and oil; if the color is dark or black, replacing the fuel or oil is the solution. Check the carburetor and fuel line. Remove the carburetor, filter and fuel line from the mower; clean the carburetor with hot water and soap and flush the fuel line. Replace the filter.
Mower Stops When Mowing
Make sure the fuel and oil levels are where they are supposed to be; if either are low, refill the reservoirs to the correct levels. Look for air leaks; these result in small holes that form in the casing, loose or missing bolts or loose or missing gaskets. Check the mower blades for obstructions, brakes or bends. Examine the fly wheel to see if it has been damaged or snapped. Clean the carburetor and air filter with hot water; allow these to dry before reassembling. Replace the filter.
Mower Runs Rough
Examine the color of the fuel and oil; if the color is dark brown or black the fluid should be replaced. Clean the spark plug and spark plug wire; use a wire brush to clean the wire, tip of the spark plug and the inside of the spark plug chamber. Clean the carburetor; look for damage during cleaning such as rust or cracks. Replace the air filter.
Mower Doesn't Restart After Stopping
Fill the fuel or oil to the proper level; both will stop the mower engine if they fall below a certain line in the reservoir. Check for excess dirt or oil on the spark plug which causes "fouling" or misfiring; clean the spark plug, spark plug wire and chamber with a wire brush. Look to see if the throttle is in the "off" or "choke" position; this will cause the engine to not engage.
Mower Vibrates While Running
Check for loose blades; tighten the blades if there is play or the blades wobble. Clear out any debris or obstructions under the mower deck; obstructions cause normal vibrations to be amplified. Tighten any loose bolts or screws, especially around the engine or engine housing---loose bolts and screws can cause vibration and eventually cause damage to the mower and engine.