If your small 2-stroke outboard’s water cooling channels aren’t as clear as they could be, or there;s no water coming through, it’s a fairly easy job to whip the head off and clear them of the corrosion and salt deposits. Once you’ve done this, try painting a thin layer of ‘etch primer’, available from most chandlers, onto each surface of the water cooling channels. This should keep the corrosion and salt build-up away for a good few years longer than just leaving the metal bare.