How do you fill trim reservior on mercury mercruiser IO?

To fill the trim reservoir on a Mercury MerCruiser I/O, locate the trim reservoir cap, usually found near the engine or transom. Remove the cap and add the appropriate hydraulic fluid until it reaches the recommended level, which is typically marked on the reservoir. After filling, replace the cap securely and check for any leaks. It's advisable to cycle the trim system to ensure proper fluid distribution before checking the fluid level again.