Abstract: An exhaust pipe has an upstream-side exhaust pipe extending downward from an engine to house a catalyst for exhaust gas purification, and a downstream-side exhaust pipe located downstream of the upstream-side exhaust pipe, and extending upward from the catalyst and then bending downward. Under a configuration in which an exhaust pipe is disposed below an engine, with a simple configuration, a catalyst is hardly exposed to water.

Abstract: In a general-purpose internal combustion engine having a throttle valve and a choke valve each installed in an air intake passage connected to a combustion chamber, air sucked in flowing through the air intake passage and mixing with fuel supplied by a carburetor to generate an air-fuel mixture that enters the combustion chamber of a cylinder and is ignited to drive a piston to rotate a crankshaft to be connected to a load such as a generator, there are provided an electric motor (actuator), a throttle valve opening/closing mechanism connected to the motor to open/close the throttle valve and a choke valve opening/closing mechanism connected to the throttle valve opening/closing mechanism to open/close the choke valve in response to operation of the throttle valve opening/closing mechanism, thereby enabling to move a choke valve without need to install an additional actuator.

Abstract: In a general-purpose internal combustion engine having a throttle valve and a choke valve each installed in an air intake passage connected to a combustion chamber, air sucked in flowing through the air intake passage and mixing with fuel supplied by a carburetor to generate an air-fuel mixture that enters the combustion chamber of a cylinder and is ignited to drive a piston to rotate a crankshaft to be connected to a load such as a generator, there are provided an electric motor (actuator), a throttle valve opening/closing mechanism connected to the motor to open/close the throttle valve and a choke valve opening/closing mechanism connected to the throttle valve opening/closing mechanism to open/close the choke valve in response to operation of the throttle valve opening/closing mechanism, thereby enabling to move a choke valve without need to install an additional actuator.

Abstract: A lubricating system for a 4-cycle engine reduces overall engine size and number of parts, and simplifies engine structure. The engine includes a side cover bonded to the crankcase defining a first valve-operating chamber, and a head cover bonded to the cylinder block defining a second valve-operating chamber. Oil reservoir chambers are formed in the crankcase and the side cover. Oil supply passages are provided in the crankshaft to permit a portion of each oil reservoir chamber below an oil surface therein to communicate with the crank chamber so that the oil passed through the oil supply passages is scattered by rotation of the crankshaft to produce an oil mist. The crank chamber communicates with the first valve-operating chamber through a one-way valve. A recovery bore opens into the second valve-operating chamber for recovering oil and communicates with each of the oil reservoir chambers above the oil surface.

Abstract: In a 4-cycle engine in which a side cover defining a first valve-operating chamber is bonded to one side of a crankcase, and a head cover defining a second valve-operating chamber is bonded to a head portion of a cylinder block, oil reservoir chambers are formed in the crankcase and the side cover to surround a crank chamber and the first valve-operating chamber. Oil supply passages are provided in the crankshaft to permit a portion of each of the oil reservoir chambers below an oil surface therein to communicate with the crank chamber so that the oil passed through the oil supply passages can be scattered by the rotation of the crankshaft to produce an oil mist. The crank chamber is put into communication with the first valve-operating chamber through a one-way valve. A recovery bore which opens into a bottom of the second valve-operating chamber for recovering liquefied oil is put into communication with a portion of each of the oil reservoir chambers above the oil surface.