Abstract: An engine balancing system for a single-cylinder engine including a single primary balancer and a counterbalancer for reducing rotational vibration, wherein the single primary balancer has an axis of rotation disposed parallel to a crank shaft of the engine and is driven at the same velocity as the crank shaft in a direction opposite to the direction of rotation of the crank shaft. A cylinder of the engine has a center line which deviates from the center axis of the crank shaft and is displaced toward the single primary balancer.

Abstract: A housing for an engine cooling fan which is mounted on the top of a vertical engine output shaft with the inner space of a double wall serving as a fuel tank. The fan housing comprises a weatherproof synthetic resin outer wall forming the upper half of the fan housing and a transparent synthetic resin inner wall forming the lower half, both being hermetically integrated into one piece.

Abstract: This disclosure relates to cooling apparatus for a water-cooled internal combustion engine. The apparatus comprises a centrifugal fan driven by the engine when running, said fan having an intake air port and a discharge air opening. A rotary screen is also driven by the engine, the screen being disposed over the intake air port of the fan and substantially preventing debris from entering the intake air port. The apparatus further includes a cooling radiator, and a spiral-shaped duct connecting the radiator with the fan discharge air opening. Further separating means is provided in the duct for removing debris from the air, the separating means being at an intermediate part or at an end part of the duct.

Abstract: A housing for an engine cooling fan, which is made up of a double wall construction with a cooling air intake passage arranged at the center and with the space in the double wall construction serving as a fuel tank. Extending in the direction of an engine output shaft, the cooling air intake passage is made up of a nearly cylindrical wall combined to the housing outer and inner walls at both ends, wherein a recoil starter is directly installed concentrically with the engine output shaft.

Abstract: The breathing device for the 4 stroke engine includes a first separating chamber formed as a tappet chamber and a second separating chamber provided above a crank case. The second separating chamber is arranged above the first separating chamber. The crank chamber and the first separating chamber are communicated to each other by a first oil return port and a first vent arranged above the first oil return port. The first separating chamber and the second separating chamber are communicated to each other by a check valve. The second separating chamber and the crank case are communicated to each other by a second oil return port.

Abstract: A suction air passage of the side-valve type of internal combustion engines is composed of a pipe-shaped portion which is integrated into the cylinder, for example by means of metal mold, and is opened at its outside, and a cover which is fixed to the pipe-shaped portion to close the opening thereof.

Abstract: An engine stopping device for rendering an internal combustion engine of a spark ignition type by grounding an ignition circuit includes a contact section for achieving grounding which is exposed to air flow passing through an engine cooling air passage, to clean off dry grass or other foreign materials from the contact section.

Abstract: A liquid-cooled internal combustion engine including a cylinder (1) and a cylinder head (6) wherein cooling liquid chambers (4, 9) are formed around a combustion chamber and wherein the cylinder (1) and the cylinder head (6) are interconnected through sealing means. The sealing means arranged on the contacting end surfaces of the outer shells (5, 10) of the cylinder (1) and the cylinder head (6) comprises a resilient sealing member (23, 24, 27), and the sealing means arranged in the contacting end surfaces of the inner shells (3, 8) of the cylinder (1) and the cylinder head (6) comprises a metallic sealing member (21, 21', 25).

Abstract: An integrated fuel control system for a gasoline engine including a linkage composed of a plurality of pivotable members which enables an operator to effect control of the choking condition of the gasoline engine and the magnitude of its power satisfactorily through a single operating element.

Abstract: In the present invention, a second expansion chamber which includes a second diffuser is provided in pneumatic connection with the prior art first expansion chamber of an exhaust system for a two-cycle engine. The second expansion chamber creates a second pressure drop or relative vacuum substantially adjacent the point of pneumatic connection between the first and second expansion chambers, which acts to draw-out the exhaust gases present at the rear-cone shaped portion of the first diffuser. The second pressure drop or relative vacuum created by the second expansion chamber of the present invention thus overcomes the deficiencies caused by the pressure increase produced by the rear-cone shaped portion of the first diffuser. Several embodiments of the present invention are disclosed.

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: A cooling system of a liquid-cooled multicylinder engine of the two cycle type, wherein a crank shaft is journalled by bearings housed in bearing housings of a small diameter mounting therein airtight seal members as well as the bearings and located at opposite end portions and an intermediate portion of a crank case consisting of upper and lower members, cylinders are arranged on the upper end surface of the upper crank case member, and each cylinder has a suction conduit attached to one side thereof and an exhaust conduit attached to the other side thereof, includes a centrifugal pump driven by the crank shaft for circulating a cooling liquid and located in a recess on the suction side of the crank case between cylinders, with the axis of the pump being parallel to the crank shaft.

Abstract: A non-contact type seal between two adjacent crankchambers of a multiple cylinder two stroke engines includes a sealing member fitted to the crankcase to encircle the crankshaft or the sleeve fitted to the crankshaft with a slight clearance between the sealing member and the crankshaft or the sleeve. A lubricant oil passage is formed in the sealing member to open to the clearance between the sealing member and the crankshaft or the sleeve so that the clearance is filled with lubricant oil which is to be supplied to the bearings at the opposite sides of the sealing member. The seal between the two crankchambers is provided by the lubricant oil in the clearance.

Abstract: Internal combustion engine having one or more cylinders and an engine cover encircling the cylinders with a space for defining a cooling air passage therebetween. The engine cover is made of a non-metallic resilient material such as rubber or resinous material and secured to the engine. The engine cover is formed at its inside surface with one or more projections which are adapted to be fitted to the spaces between cylinder cooling fins.

Abstract: A rotary engine wherein a side port is formed in one side housing, and a main peripheral port, communicating with the side port, and a bypass peripheral port, communicating with a bypass passage formed in another side housing, are formed in a rotor housing, the side port being maintained in communication with the carburetor through a passage formed in the rotor, while the bypass peripheral port communicates with the carburetor by bypassing the passage in the rotor. Respective valves are mounted in the main peripheral port and the bypass peripheral port, and the two valves are closed or throttled at low engine speeds. The bypass peripheral port opens at higher engine speeds than the main peripheral port.