Lots of problems with ethanol going into older engines whether it be a lawnmower or on a boat. Since these engines are 10+ years old and sometimes the car sits, premium 93 octane fuel has ethanol which can separate into water over time. Versus non-ethanol which is 90 octane and will not separate. Comments?

https://b3cfuel.com/

Although it is made for small carb engines, gas in the tank oxidization is all the same, so either Mechanic in a Bottle or Ethanol Shield should help.