Whenever you use the boat in the saltwater a small amount of salt builds up on the water galleries. Over time the salt gets accumulated and its presence is increased. Flushing the motor helps to remove the salt deposits, but you cannot remove the embedded salt completely. The only way to resolve this issue is to replace the powerhead gaskets. Thus you can accomplish the goal of removing the salt deposits completely. For more details visit, technologynewsupdate.tumblr.com/post/626959925552332800/replacing-outboard-powerhead-gaskets