Last year I purchased a small Smoker craft fishing boat that had a 1968 Evenrude electric start engine. It was in very bad condition and was a mess. I could not keep I running. I dumped the gas ,put in fresh gas & Opti-2 and believe it or not it started right up and after 20 min. of running it was hardly smoking. I then took it fishing & it ran so smooth with no oily water that even the other boaters were impressed. My next crabbing trip I ran out of gas & had to be towed back to the marina to get gas & oil (yes 2 strokes do use more gas). They only had Chevron so that’s what I used. It at once started smoking & leaving a oil slick on the water. When I got home I again dumped the gas & put in Optic-2 with no problems since. I now also use Optic-2 in chainsaws & weed eater. WHAT A GREAT PRODUCT !