87 is probably the way to go but most marinas have 89 which has probably been sitting around with lots of water in it and turned to crap so thats why I throw in a can of seafoam now and then just in case. A friend of mine works on everything and told me that 8 out of 10 of the motors that he works on have crappy gas or water in the carb from condensation so he recommends running everything dry or pickle it with seafoam or stabil but he thinks seafoam is better..Who knows..I've had motors I've ran hard with little maintenance for years and others that I did everything by the book and they still blew up...One thing for sure the gas on the market now is bad and is getting worse as far as outboards are concerned ... Frank