Good day, I own the 42" Fast Trak SD and enjoying the season, fantastic results cutting. Have read different opinions concerning the fuel octane being used. I have been using 89 and read using 91 is better for the Kawasaki FX600V engine. Every other fill I use a little Lucas fuel cleaner and lubricator that I use on my cars, seems to keep everything in the system clean and running smooth. What are some opinions from the hustler board?