6 Essential Outboard Winterization Products

Winterizing your boat’s outboard motor properly is something you don’t want to overlook when it comes to storing your boat during the offseason. 

Essential outboard winterization products

Here at Boats.net, we’ve published about a dozen articles and videos related to the how’s and why’s of outboard winterization, but we’ve never published an article that dives straight into the products used for this crucial offseason maintenance process. With that in mind, here are 6 essential winterization products you need to prepare your outboard for offseason storage.  

Fogging Oil

Condensation forming on the cold metal walls of cylinders leads to corrosion. Spray those cylinders with fogging oil before the outboard is put into winter storage to protect them from corrosion

Mercury marine fogging oil

Mercury Quicksilver corrosion guard

Corrosion Guard

Any exposed metal parts or components on the powerhead of an outboard are susceptible to rusting. All external metal surfaces should be sprayed with corrosion guard before putting the outboard engine into storage. 

Fuel Stabilizer

Untreated fuel absorbs moisture from the air, until the fuel undergoes phase separation, which will require the fuel tank to be drained. The fuel tank should be filled with fresh fuel and treated with stabilizer. Run the motor for a couple of minutes to draw fresh, stabilized fuel into the fuel system before putting it in storage.

Mercury QuickStore fuel stabilizer

Honda HP marine coolant


A cooling system flush should be part of your outboard’s regular maintenance schedule even if it’s not going into storage. However, the cooling system should be flushed with marine coolant to prevent corrosion, and to keep any water trapped in the system from freezing during winter in colder environments. 

Lower Unit Oil

Changing the engine oil is part of any outboard’s regular maintenance schedule, but the lower unit oil is often overlooked. Both the engine and lower unit oil (gear lube) should be drained and replaced as part of the winterization process, and replacing the lower unit oil in particular can be done in minutes with the lube and a hand pump.

Buy Yamalube marine gearcase lube

Buy battery tender

Battery Tender

Your outboard’s battery should be disconnected and removed as part of the winterization process. Keeping the battery connected connected to a battery tender helps preserve it while it’s in storage. Battery tenders are also known as smart chargers or trickle chargers, and they provide charge to the battery only when it needs it to prevent overcharging. 

Winterizing an outboard is an essential part of annual maintenance. Here are 6 more essential outboard winterization products to consider. Watch the video above for a rundown of what an outboard requires for annual maintenance and winterization



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