What makes mower smoke on start up?

Smoke on startup from a mower can be caused by several factors, including oil leakage into the combustion chamber, a clogged air filter, or using the wrong type of fuel. If the oil level is too high or if the oil has become contaminated, it can lead to excessive smoke. Additionally, a dirty spark plug or a malfunctioning carburetor can contribute to poor combustion, resulting in smoke. Regular maintenance can help prevent these issues.