I recently posted a question on LS about 2 cycle fuel recommendations... It seems most manuals recommend 89 or higher, which is somewhat unclear... I have a Lazer 25/60 Kohler, and am wondering if Exmark recommends running 93 octane gas. Kohler manual stated 87 or higher. I guess my question is, is 93 too high, can these air cooled engines be damaged with it? I also posted that recently I put a tank of 93 in a Briggs and Stratton engine that had previously only had 87, and now it seems to run rough, and belch black smoke, just wondering if the different octane gas is responsible. Thanks.