I have an MS361 that was ported and muffler modded by Brad. I have been using 91 octane pump gas that has the 10% ethonal. I work at an airport so I have easy access to 100LL. Should I switch, or just keep using the pump gas?
It won't like idle as well or have as good of throttle response. That's been my experience. I'd stick with the pump gas if it were me.