Which is recommended for maintenance for an inboard engine?

For maintaining an inboard engine, it's recommended to regularly change the engine oil and replace the oil filter according to the manufacturer's schedule. Additionally, check and replace the fuel filters, inspect the cooling system, and ensure the impeller is in good condition. Regularly inspect belts, hoses, and electrical connections for wear, and perform routine checks on the battery and ignition system. Finally, ensure that the engine is winterized properly if stored during colder months.