Basic Lawn Mower Repair


Lawn mowers are a mechanical tool that can break down due to repeated use and age. Lawn mower owners can choose to take the machine to a repair shop or attempt repairs themselves. Depending on the type of repair, the cost for a professional repair may be unwarranted. Basic lawn mower problems are often caused by common issues found in every machine. These problems can be repaired using minimal tools and a basic understanding of what to look for to solve the problem.

Fuel Problems

Fuel-related issues can cause stalling. Common fuel problems include bad fuel, old or burnt fuel. These problems cause misfiring in the motor which causes stalling. Water in the gas will cause stalling. Look for droplets or condensation inside the fuel line, carburetor, or in the gas tank. Water must be evaporated or drained completely to resolve this problem. Air bubbles can cause the same problem. Examine the fuel line and carburetor for cracks or holes to find air leaks. Using 2-cycle or mixed fuel changes the viscosity and allows oil into the engine; this can cause engine damage. Drain the engine and use correct fuel.

Mowing Problems

The sharpness of the mower blades determines the quality of the work. Grass with jagged and rough edges are a sign of a dull blade; have the blade sharpened. Uneven grass is a sign of an unlevel mower deck or blade. The blade should be tightened and the wheels of the mower must be at the same adjusted level for both front and rear. Loud noises followed by sudden motor stopping means the blade or rod has been damaged by a sudden impact with a hard object. Replace the blade or rod and have the engine serviced by a small engine repair shop to ensure no further damage. If the mower is running too fast the grass will be uneven and clumps of grass will be discharged from the mower. Check and adjust the throttle, choke and governor to ensure the correct settings.

Mechanical Problems

Mechanical problems cause continuous stalling. Check the settings of the throttle, choke and governor. Settings for these items can be affected by broken or worn springs, hinges, wiring or levers. Non-starting motors indicate fuel, oil or electrical problems. The age and condition of liquids, spark plug and any hoses or connecting wires may cause problems. Inspect the fuel and oil for age or debris; examine the spark plug hoses and wiring for age and damage. Replacement of old fuel or mechanical items is warranted in case of doubt. Lawn mower batteries also need testing and recharging occasionally to ensure proper voltage. Smoke emitting from the motor indicates burning oil, burning gas or water has entered the engine depending on the smoke color. Dark smoke indicates oil burning; light smoke indicates fuel or water and can be caused by an electrical shortage.


Troubleshooting basic problems can eliminate costly repair later. Change the fuel and oil at least once per year at the end of the season or more frequently if the motor shows signs of trouble. Clogged carburetors or air filters prevent fuel from entering the motor at the correct amount; cleaning the carburetor and air filters prevents this problem. Leaking fuel or oil is determined by looking for various signs: burn marks or shiny coating on the exterior of the motor housing indicates it is covered in fuel or oil; streaks around the gas or oil fill holes indicate tipping or overfilled chambers. Loose blades, bolts and screws or obstructions under the mower deck cause mower vibration. Improper cleaning allows dirt and debris to build up on the spark plug, wires, carburetor and air filter causing improper firing of the motor.


Regularly scheduled maintenance eliminates many causes of lawn mower repair. Cleaning the mower deck, blades and engine housing after each use removes dirt and debris. Checking the level and condition of fluids before mowing or filling tanks ensures proper flow of fuel and oil into the engine. Visually inspect the mower parts before use.

Keywords: lawn mower engine, lawnmower troubleshooting, basic lawnmower repair

About this Author

Jack S. Waverly is a Pennsylvania-based freelance writer who has written hundreds of articles relating to business, finance, travel, history and health. His current focus is on pets, gardens, personal finance and business management. Waverly has been writing online content professionally since 2007 for various providers and websites.