NOTE: The use of non-detergent oils, multi-viscosity oils (other than as specified), non-FC-W rated synthetic oils, low quality oils or oils that contain solid additives are specifically not recommended.
Now having said that, just about any oil works. Most of the professionals here will probably tell you that there have been VERY few (if any) engine failures that could be attributed to oil type. use what ever you want but change it frequently (at least once a year at the end of the season)
I run their marine synth and not had issue but like the previous thread states, this is discussed often and everyone has their own opinion. I also run it in everything except my lawnmower for years. Tractors, cars, diesel truck, compressor, generator, etc. My mower was the only one that seemed to have starting issues with it and loss of fuel economy. So each will have their own results with it.