I had a Yamaha HPDI for 4 years before I sold the boat. It never had anything but ethanol fuel in it. The only non-ethanol fuel around hear is premium and one place with 89. Yamaha told me to only run 87 in it so thats what I did. I always ran Ringfree (45 bucks a quart!) and Marine Stabil in every tank . I never had any problems but I wish someone would start selling non-ethanol 87. My new Cat will have a Pro XS 250 on it and Merc also recommends 87 but some say 89 is ok. I dont know whether to run ethanol 87 or non-ethanol 89.