I sho do believe in that stuff. I hadn't run any through my tank in over a year but my boat had gotten to running tough and not staying cranked. I put a can in Friday and by the time the weekend was over, I could bump the key one time and itd crank. It runs like a top now. No more shaking or missing like it was doing. I've been putting StaBil in it which you have to do with ethanol in gas these days but a word of advice. Run you a can if seafoam every few tanks.