I don't know about using too much, but doubt it will hurt. My small engine mechanic says that he does not see Stabil working well on the newer gas. He sees a lot of messed up carburetors on engines that have used it. He has seen much better results with a Startron product. I don't remembr the name, but it's available at Advaned Auto Parts and is blue in color like windshield washer fluid.