Now is the time to replace the fuel filter as well. If your rig doesn’t have a water-separating fuel filter, I strongly recommend you add one. Quality brands like Racor are head-and-shoulders above the rest because they use better components, and finer-micron filters. However, the typical marina brands are fine, too, and work well to filter out water, dirt, and other contaminants. Placement in the fuel line should be between the tank outlet and engine inlet.