- Apr 20, 2016
Hello, I bought a Catalina 27 last year which has a Universal 5411 diesel inboard. The previous owner was nice enough to fill the tank for me. As you probably know, this engine is like the Prius of diesels and barely uses any fuel and at the end of this second summer of sailing, I'll probably still have 3/4 of a tank left. I'm in Vermont and we haul out our boats every year and last winter I treated it with diesel fuel treatment. I'm not having any problems at all with the fuel or engine but when does diesel become too old to use any longer? Can I just keep treating it every winter or should have the old fuel pumped out and refilled at some point?