My 5hp,1987 Nissan outboard has a severe rust problem inside the gas tank. I've looked into replacing it. They make a retrofit plastic replacement tank for $180 however, I found a sealer (see link) that seems to fix the problem at a fraction of the cost. Has anyone use this product by Caswell Inc? How have other sailers out their solved this problem? The engine runs like a top other wise, but I have to keep cleaning out the filter screen. Any comment? Thanks