I don't pretend to know a bunch about this, but I used to run a mom & pop fishing resort and had to maintain the rental outboard motors, also had a small sawmill at one time and was advised by the small engine guy up my way to not use marine oil in the chainsaw and vice verse. Now I use Opti-2 from day one on my bikes and just run em'. So far as I know, with no ill effect. No stink as I'm cutting firewood and 100-1. I know some will say "don't do that" but a lot of us here have switched over and really like it. Nothing wrong with the advise you've already gotten but I can't say for sure about the marine oil designed for a water cooled engine in an air cooled engine. As for synthetics, they are not all the same either. I used to use Amsoil sabre professional which is also rated at 100-1. Others have a richer mix. I'd say, follow the manufacturer's guidelines. Lots of different opinions on this from knowledgeable people, mechanics and such who do not agree with each other. In the end it's your call. Considering that in China they are probably using used motor oil from a truck for these little motors there's probably a lot of wiggle room.
SB
