Fuel is supplied stably to the engine for models under severe operational conditions. The magnetic core 34 is inserted in the solenoid coil 32 in the box 31. The movable valve body 38 is provided in the box 31. The valve body 38 is pressed by the plate spring 44 so as to close the fuel injection opening 37. The check valve 24 is provided on the fuel feeding passage 48. The diaphragm partitions between the air pressure supply passage 25 and the internal of the box 31. The pulsatory air pressure of about 20 to 100 kPa generated in the crank chamber is applied to the fuel in the box 31 through the diaphragm 26. Fuel is introduced into the fuel injector without pressurization and confined by the check valve, and the fuel is pressurized using air which is not affected very much by the force due to acceleration. The air pipe 27 is fixed to the valve body 38 and diaphragm 26, and communicates between the air pressure supply passage 25 and fuel injection opening 37. The fuel introduced into the fuel injector 30 is confined by the check valve 24, and is pressurized with the pulsatory air pressure from the crank chamber at a constant pressure. When injection, air is injected and injected fuel changes to mist. The supply of fuel is stable even under severe operational conditions, the combustion efficiency is improved, and the output of the engine is increased.
