BigBendFishing.Net

93 in a GEO is wasting some Octane points. In a high compression engine, 150 psi or better, you need to run higher octane. In a lower compression engine, 120-145 87 or 89 is actually better. The 93 in the lower compression engine will not burn as completely as it does in the higher compression motor, thus creating more carbon and deposits that you are trying to eliminate. There is a possibility that you have some gunk in the injectors and on the valves. There is no such thing as a mechanic in a bottle or can.with that said, the only thing I have seen work to clean out the fuel system and help with carbon deposits on valves(other than remove and clean) is Techron. Put a double dose in the tank, run it for at least 20 miles, then park overnight. This gives the chemical time to dissolve the crud, then the next morning when you fire it up....flush goes the junk and the rest is clean and running better.

There is less energy in a gallon of gas/ethanol than in a gallon of pure gasoline, hence you will get fewer miles per gallon (and less power out of you outboard). E-85 fuel is even worse, both in term of miles-per-gallon and damage to both car and boat engines. Thank the big farm conglomerates (Archer-Daniels-Midland, CONAGRA) for buying off the politicians and shoving ethanol fuel down our throats. Now fuel is just as expensive, we need to use more to go the same distance, and food prices have soared because corn is now more valuable as a fuel rather than food. I think I've lived too long.