Murray lawn mowers are well-built and reasonably priced lawn care machines. The horsepower and sizes vary, but all have the same basic motor components and drive system. As with any machinery, though, problems may arise needing inspection and repair. The two-cycle lawn mower engine is a relatively simple machine and can be serviced quickly with the proper tools and information about where to find the problem.
Lawn Mower Will Not Run
Check the spark plug connection. Use a round metal file or coiled piece of sandpaper to clean the spark plug socket to ensure good contact with the spark plug lead. Remove and clean the spark plug of any excess oil and dirt. Verify the manufacturer's recommended spark gap between the center and side electrodes at the bottom of the plug.
Check the air filter. If it is dirty and black with oil and contamination, clean it with soap or a good degreaser and allow to thoroughly dry. Do not install a wet air filter. Check the carburetor area directly under the air filter for any dirt, small twigs or bits of grass. The carburetor is a hollow, round assembly with a lift flap allowing air and gasoline to mix before being added to the engine.
Check the fuel line between the gas tank and the carburetor. Make sure the gasoline flows freely to the carburetor. Check the gasoline for any water or other contaminants. If the gasoline is contaminated, drain the tank completely, clean it thoroughly and allow it to dry completely. Dispose of the contaminated gasoline properly.
Check the oil level. Lawn mower sumps can go dry, preventing proper operation. Consult the owner's manual for proper oil amount and type of oil for your specific Murray lawn mower.
Check the safety bar at the push handle and accompanying solenoid for proper operation. The safety solenoid is located at the opposite end of the safety-cable assembly. It prevents spark plug fire if not retracted by the cable attached to the safety bar. Adjust the cable tension, if necessary.
Lawn Mower Will Not Cut Grass
Disconnect the spark plug (for safety) and check underneath the cutting deck. When turning or tilting the lawn mower, be careful not to spill oil or gasoline even if the caps on the tanks are secure. Examine the blade for sharpness or large nicks in the cutting edge. Take a metal file or specialty sharpening tool to return the blade to original specifications. A dull blade will "push" the grass, not cut it.
Check the lawn mower's deck height. This adjusts the distance between the blade and the grass. Raise or lower the deck height at each corner using the wheel adjustments. A deck too high will miss the grass, and too low will contact the soil and damage the turf instead of cut the grass.
Clear all grass ejection areas at the clipping bag or other areas under the deck possibly clogged with mulch and clippings.
Lawn Mower Runs Inefficiently
Check the manufacturer's specifications for the proper gasoline type for the mower. Drain and properly dispose of any gasoline in the mower. Leaded gasoline or high-octane fuel will adversely affect engine operation. Replace with the gasoline specified by the manufacturer. This step eliminates fuel as a possible source of poor engine performance.
Check the manufacturer's specifications for the proper oil type for the mower. Oil too heavy or too light will affect engine lubrication. Drain and properly dispose of any oil not specified for the engine type.
Check the manufacturer's specifications for proper blade size. A replacement blade too large or too small will affect engine operating balance. Replace the blade if it is the wrong size or otherwise does not meet the manufacturer's specifications.