Abstract: A by-pass canal of a cooling system in an internal combustion engine for bypassing a cooling liquid between a thermostat and a liquid pump in a shortcircuit. The by-pass canal is formed in a cylinder, and a cylinder head of the engine or formed in a cylinder, a cylinder head and a crank case of the engine without extending outside of the engine.

Abstract: A by-pass canal of a cooling system in an internal combustion engine for bypassing a cooling liquid between a thermostat and a liquid pump in a shortcircuit. The by-pass canal is formed in a cylinder, and a cylinder head of the engine or formed in a cylinder, a cylinder head and a crank case of the engine without extending outside of the engine.

Abstract: A crank mechanism such as in a two stroke internal combustion engine has a lubricating system comprised of an oil passage formed in the crankarm and the crankpin with one end opening to the bearing between the connecting rod and the crankpin and the other end to the side surface of the crank arm facing to the main bearing. Lubricant oil is supplied through the main bearing and an oil receiver which is located between the crankarm and the main bearing. The oil receiver is held in position by being axially compressed and resiliently deformed between the crankarm and the main bearing. For the purpose, the oil receiver is formed with a resiliently deformable portion.

Abstract: An actuation device for a tachometer adapted to transmit the revolutions of an engine crankshaft to the tachometer, wherein the oil pump of the engine is utilized as a speed reducing mechanism for transmitting the revolutions of the engine crankshaft to the tachometer after the engine speed is reduced. A cable connected at one end to the plunger of the oil pump whose speed is reduced by means of a gearing is connected at the other end to the tachometer. Thus, by utilizing the oil pump, it is possible to transmit the revolutions of the engine crankshaft to the tachometer without requiring a speed reducing mechanism provided exclusively for the tachometer.

Abstract: Variable displacement type lubricating oil pump for two cycle engines having a displacement control element which is rotated in response to the engine throttle valve position. The control element has a cam which is so shaped that the pump displacement is changed in accordance with the engine throttle valve position. When the control element is accidentally disconnected from the engine throttle valve control device, the control element can be rotated beyond the minimum displacement position which corresponds to the engine idling position, whereby the pump displacement is increased than in the idling position.