Some common issues with Mercruiser engines include overheating, loss of power, and difficulty starting. Overheating can be caused by a malfunctioning thermostat, impeller, or blocked water passages. To resolve this, check and replace these parts if needed, keep the water passages clear, and ensure proper coolant levels. Loss of power can be due to dirty or clogged fuel filters, worn spark plugs, or faulty ignition components. Resolve this by cleaning or replacing the filters, spark plugs, and ignition parts as required. Difficulty starting may result from a weak or dead battery, fuel system issues, or a faulty starter. Check and charge/renew the battery, inspect and clean the fuel system, and repair or replace the starter if necessary. Additionally, routine maintenance and regular inspection can prevent these issues from occurring.