Clean Up the Boat
Give your boat, and your outboard, a thorough cleaning before extended storage. Always make sure that any item or area in your boat is bone-dry before closing it up or sealing it off. Where applicable, a coat of sealant or wax will serve as a well-worth-it protectant.
Tip: This may be the best time to pull the boat out of the water and clean the hull as necessary. Remove any marine growth or barnacles with a thorough washing or sanding.
If appropriate for your boating locale, now would be an excellent time for a new coat of bottom paint, too. Make certain to adhere to local legal and environmental requirements and appropriate safety precautions during these procedures.
Inspect Everything
Few things are more important than the visual inspection you do before extended outboard motor storage. Start at the top of the cowling and work your way down to the skeg. Be sure to pull the cowling and the propeller off, too. Look for anything that appears damaged, missing or out of place, and repair or replace as needed.