Replace the washers on the fuel filter connections.
photo by Matt wright, 2007
Remember those special fuel line bolts you carefully set aside? Sitting on those will be a special pressure washer. They are usually either copper or aluminum. Remove the old washers and replace them with the new washers that match. The washers are usually different from one side of the fuel filter to the other. You'll place one washer on the bolt before you slide the fuel line on, and one after.