Outboard Motor Oil Change Tips for Storage

Oil protects every vital internal component of a boat's outboard engine, ensuring its health and longevity. And when it comes to storage, it’s crucial to change the outboard’s oil before letting it sit for months.

Changing the oil in the outboard when winterizing both it and the boat itself makes things much easier when it's time to de-winterize the motor without any unexpected problems. Here are some tips on doing outboard oil changes in preparation for winter storage. 

Why Change Outboard Engine Oil for Storage?

Whether you’re storing your boat for winter or during hurricane season, its engine lubricants should always be changed during these long periods of inactivity.

Engine oil protects the motor even when it’s idle, providing a protective barrier between the metal surfaces within the engine. It also protects against any water that might get in. Even a small amount of water in a crankcase or a gearcase will corrode the internal surface and components, particularly during winter storage.

What if the Outboard Isn't Due for an Oil Change?

It doesn't matter if the outboard recently had an oil change done on it. If you’re going to store it away for an extended period of time, you should put in fresh engine oil right before it goes into storage.

Oil that isn't fresh out of the bottle will be full of contaminants from combustion gasses, carbon deposits, and microscopic metal fragments suspended within it. Contaminants in the engine oil slowly break it down and corrode the motor’s interior. By replacing the oil before you store your boat and/or outboard motor — even if it’s relatively new oil — you’ll be removing these harmful contaminants to protect the motor during its storage period.

What Else Besides Changing the Oil?

As well as changing the engine oil, fogging oil should also be used to winterize an outboard motor. Fogging is the process of ensuring all the internal components of an engine, such as seals and bearings, are coated in a protective lubricant. The fogging oil is sprayed into the carburetors or injection system while the engine is running, which causes it to cloud within the engine and coat all the surfaces.

What Engine Oil Should Be Used for Outboard Storage?

The engine oil used to store an outboard motor should be the same one used for regular oil changes. Whether you use OEM motor oil made by your outboard’s engine manufacturer or another high quality aftermarket oil, keep in mind that marine engine oil and automobile engine oil are not the same. Never cut corners by using any engine oil other than what’s recommended by your boat engine’s manufacturer.

• Oils with an API rating that begins with a letter ‘S’ are only for use with gasoline powered motors
• Oils with an API rating beginning with ‘C’ are only for use with diesel powered engines

Don’t forget to change the oil filter as well as the oil itself before you put your outboard motor away for the offseason.

Give your boat’s engine the care it deserves both in and out of the water. Whenever you’re ready to take your boat and its outboard out of storage, watch the video below to learn how to dewinterize an outboard motor.