Bought a can about 7 years ago, lifted up the "hood" on my OB, and went crazy with the corrosion guard on all the major components that were made of metal. How good is it? I had a problem with my starter and a repair shop took it apart. The shop said the starter looked brand new inside. So spend the 8 bucks and keep the engine looking like it was the day you bought it. FYI, the engine is 20 years old this year.