I have a 95' 115HP Mariner and a 95' 15HP Mariner, both 2 strokes. They both purr like kittens. I have had them 9 years and the previous owner was a salesman at the Marine dealership. The only thing he did other than maintenance was replace a bad stator on the 115. They better run well after I said they purr. Hope I didn't put the kybosh on them.