The part(s) or condition(s) listed below for the symptom Lawn mower overheating are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
All air-cooled small engines have cooling fins manufactured right into the engine's cylinder head and short block. These fins help to dissipate the heat from the engine. If the fins get clogged with dead grass, leaves, or other debris, they won't allow the engine to cool properly, and the engine will overheat.