What makes a briggs and stratton 4.5 engine run too rich?

A Briggs and Stratton 4.5 engine can run too rich due to several factors, including a clogged air filter that restricts airflow, a malfunctioning carburetor that allows excessive fuel into the mixture, or a faulty fuel pump that delivers too much fuel. Additionally, incorrect adjustments to the carburetor settings or using a wrong fuel type can contribute to a rich condition. Regular maintenance, including cleaning or replacing filters and inspecting the carburetor, can help prevent this issue.