Abstract: A decompression apparatus includes: a cam shaft having exhaust cams that each open an engine exhaust valve; a release pin rotatable about an axis parallel to the cam shaft between decompression and decompression release positions; a decompression plate fixed to the cam shaft with an opening where the cam shaft is inserted; a weight swingably attached to the decompression plate, radially outward by a centrifugal force; a biasing unit that biases the weight radially inward; and an interlocking mechanism that rotates the release pin with the rotation of the weight. A first flat section is formed on an inner peripheral edge of the opening. The cam shaft has a second flat section that abuts against the first flat section and a supporting surface on a same plane as the second flat section. The outer peripheral surface of the release pin abuts against and slides on the supporting surface.

Abstract: In a gas-liquid separation device in a vibrator engine according to the present invention, a crank chamber and a rocker chamber communicate with each other through an oil delivery passage, and a push rod chamber and the crank chamber communicate with each other through an oil chamber and an oil discharge port. Oil mist generated in the crank chamber flows into the rocker chamber through the oil delivery passage, as the oil discharge port begins to resist the flow. The mist flows into the push rod chamber after the mist is made into liquid for lubrication of parts to be lubricated. Thus, the oil is returned to the crank chamber from the oil delivery passage through the rocker chamber, the push rod chamber, and the oil chamber to form a circulating path.

Abstract: In a gas-liquid separation device in a vibrator engine according to the present invention, a crank chamber and a rocker chamber communicate with each other through an oil delivery passage, and a push rod chamber and the crank chamber communicate with each other through an oil chamber and an oil discharge port. Oil mist generated in the crank chamber flows into the rocker chamber through the oil delivery passage, as the oil discharge port begins to resist the flow. The mist flows into the push rod chamber after the mist is made into liquid for lubrication of parts to be lubricated. Thus, the oil is returned to the crank chamber from the oil delivery passage through the rocker chamber, the push rod chamber, and the oil chamber to form a circulating path.

Abstract: The generation of knocking in an engine is controlled by an engine knock control system, which comprises circuit such as a magneto for generating a reference signal in synchronous with a rotation of the engine and an ignition circuit responsive to the reference signal for controlling electric supply to an ignition coil of the engine to ignite the engine. The control system further includes an ignition control circuit for maintaining an ignition timing to a second angle retarded with respect to the reference from the reference signal generating circuit when the knocking in the engine is detected by the knock sensor and for returning the ignition timing to a first angle corresponding to the reference signal when the temperature of the engine becomes below a predetermined temperature.