Even if I have to completely fill the 50 gal. tank (normally I just top off at end of day) on my 19' Glasply, it only costs an extra $7.00 to use the premium grade gas. Well worth the price! Like the others said, use good quality (brand name) gas without the fuel line eating alcohol. Keep your tanks full to reduce condensation, plus you get on the water quicker then. If your boat doesn't get used over the winter, shut off or disconnect the fuel while the engine is running. Let the engine run 'til it quits. This drains the carburater and prevents the float from sticking or the rest getting gummed up. Use fuel stabilizer if your tank doesn't get fresh fuel for longer than about 3 weeks. Well, I got a little carried away, but 92 octane gas burns hotter, runs smoother, and doesn't carbon foul a motor nearly as bad as the lower grades. This is particularily true if you do a lot of trolling with the motor.