dirty idle jet. They are hard to clean. Has small hole in middle and 4 lager holes above, is not a straight pass through. It is behind the sticker on the carb.
Overheating? the only way the motor will over heat is if you have dirt in the fins of the cylinder head, lack of oil, lean mixture due to too much oil in gas, dirty jet, Or if you are mowing in death valley. A lean condition the mower will pop and hesitate. A dirty idle jet can cause these issues especially if the mower will not idle.