Re: Better motor
An EFI outboard is a throttle body fuel injection setup. The throtle body replaced the carbs, and provides a bit better running. However the balance of the motor is identical to the carb version. It still suffers from unburned fuel out the exhaust, from the exhaust scavanging process.
The Optimax is a direct injected outboard. The Optimax has an air compressor which allows the gasoline to be forced into the combustion chamber, by this high pressure air, after all the traditional 2 cycle motor's intake and exhaust ports are closed. The air and injected oil travel thru the crankcase, as in the traditiional carb, but the simililarity ends there. The Optimax is much more efficient, complex and better on fuel and has the CARB5 rating.