DIY boat storage tip – protecting the inside of your boat engine from corrosion


As an angler, life often gets in the way of spending time on the water. Be it family, work, hunting or ice, extended sits can spell problems with your outboard engine. Without regular use, outboard motors are susceptible to aging fuel and even corrosion formation within the upper cylinder walls themselves. 

The problem stems from gravity – as a motor sits idle, oil and other lubricating compounds drain out of the upper cylinder. Ambient moisture can collect on unprotected metal and especially so where the piston rings meet cylinder walls, causing rust to form. Corrosion within cylinders can reduce an outboard’s performance and shorten its overall lifespan.


The first step to reducing cylinder rust is treating your fuel. Before parking the boat for a nap, I add a can or two of Sea Foam Marine PRO to my fuel. In addition to stabilizing fuel, Marine PRO contains lubricating oils that create a protective film on metal parts and thwart off the effects of moisture.

The second step is to “exercise” the cylinders through the simple act of turning your engine over. For older hand-pull 2-strokes, simple pull the recoil to move the cylinders. If you have a 4-Stroke, turn the engine over, then turn the key off before the combustion cycle begins. The act of moving the cylinders redistributes the lubricating oils for fresh protection. And commonsense says that the longer something sits, the greater the chances for corrosion to set in.