An attempt to reduce the HC emission of a two-stroke engine was carried out. A simple homogeneous charge combustion created with a Direct Fuel Injection (DFI) system was applied to a Personal Water Craft (PWC) engine. 1/4 HC emission of the base carbureted engine was obtained in International Council of Marine Industry Association (ICOMIA) driving mode due to the exclusion of fuel short-circuiting. Then stratified charge combustion was introduced. A numerical simulation of air and spray motion was performed and mixture formation was optimized. The low load misfiring was completely overcome and finally, less than 1/8 HC emission was achieved.