I have a two 100 gal. gas tanks on my 4 year old houseboat. I usually at the end of each season top off each tank and add enough Stabil to treat the amount of the final top off. I did this in the fall of 2002. The river conditions were so terrible in 2003 I didn't use enough fuel to warrant getting any fuel. I have not fueled up this season yet and still have about 100gals. of fuel that was treated in the fall of 2002. <br /><br />I was hoping to use most of the old fuel this season but that didn't happen, so I have fuel that has been treated but is at least 2 years old. Should I continue as I have and top off with another 100 gals and add Stabil for that amount or does someone have some other suggestions?