Nowadays, human realize to the environment pollution cause from old engine and use the engine misapply. These engines will cause the problem such as air pollution and cannot use the engine to work at the maximum efficiency and fuel consumption. The new of control technologies can solve problems from misuse engine by an electronic control unit work with many sensors. Optimization of electronic control unit (ECU) makes an engine to work in maximum efficiency and decrease the environment pollution. In this research, Port-fuel injection spark ignition engine (PFI Engine) fuelled with gasoline is use as the boat engine. To use car engine as boat engine, the control system has to be modify and tune up for proper condition. For the method, the parameters that used to control and optimization are the boat's running condition to tune up injection timing, injection duration, ignition timing, and also the engine special function. And this paper aim to investigate and improve performance, efficiency and emission of misapply engine. After that we plan to do research on each part of the system that makes the engine run with alternative energy such as gasohol (E10 to E85) to reduce the emission of greenhouse gas and environment pollution.