When should a lawnmower muffler be replaced?

A lawnmower muffler should be replaced if you notice excessive noise during operation, which may indicate damage or wear. Additionally, if there is visible rust, cracks, or holes in the muffler, it can lead to exhaust leaks, reducing performance and efficiency. Regular maintenance checks can help identify these issues before they become serious problems. Always consult your lawnmower's manual for specific guidelines on muffler replacement.