Lawn mower issues often start small—hard starting, surging, belt squeal, uneven cutting, or vibration—but can quickly lead to downtime if ignored. This guide covers the most common problems found on commercial mowers, zero-turns, riding mowers, and walk-behind units, along with practical troubleshooting steps for fuel, airflow, spark, blades, belts, and deck systems. You’ll learn how to identify whether the issue comes from the engine or cutting system, what checks should happen first, and when deeper inspection is necessary. With the right maintenance habits and replacement parts ready, operators can reduce costly breakdowns and keep mowing equipment working efficiently through demanding conditions.