Abstract: A method for manufacturing a multiple-wall synthetic-resin case having vertical multiple walls. The case is manufactured by integrating both upper and lower halves into one piece by jointing together; more specifically, each of the vertical walls is manufactured by jointing the upper wall formed in the upper half to the corresponding lower wall formed in the lower half. The jointing portions of the respective pairs of mating vertical walls are provided with different elevations so that they form their individual closed loops on the respective planes of elevations different from each other, conductive wire is inserted between the jointing surfaces of the upper and lower wall halves at each mating portion and apply high-frequency-heating to the conductive wire for welding the jointing surfaces.

Abstract: A muffler for work vehicle V-type internal combustion engines is disclosed, which is mounted in a horizontal sideway position, with its axis placed perpendicularly with the longitudinal vehicle axis, kept a proper distance from the chassis or vehicle body so that it is disposed in full exposure to the atmosphere for proper cooling. A pair of spaced inlet ports are provided in the muffler, at locations adjacent to opposite ends thereof for receiving the exhaust gases from the engine through a pair of parallely extending, parallel exhaust pipes directly interconnected between the combustion chambers of the two cylinders and the muffler inlet ports, without using the conventional intermediate flexible corrugated connectors.

Abstract: A cooling system for V-type engine comprises rows of left and right cylinders arranged in V-type and having coolant jackets, respectively. A coolant pump having a pump shaft parallel to a crankshaft is arranged with a V-bank and at a place away from each cylinder in an axial direction of said crankshaft, and coolant jacket inlets are provided on the side of the coolant pump of each cylinder. Alternately, the coolant jacket inlets of the cylinders are opened respectively at one end face in the direction of the crankshaft of a crankcase-forming member, and a distributing exit passage is defined by joint faces of said crankcase-forming member, a pump casing and a pump casing cover respectively.

Abstract: An improved exhaust system for water craft engines is disclosed, which consists in the main an exhaust manifold connected to the cylinder exhaust port of the engine, an exhaust pipe joined at one end to the exhaust manifold and a diffuser connected at one end to the other end of the exhaust pipe and at the other end to the rest of the exhaust system including a muffler and steam separator. The exhaust pipe is divided into two axial parts, the first vertical, largely U-shaped pipe portion for direct connection to the exhaust pipe at downstream thereof and the second horizontal pipe portion for connection at one end thereof to the first pipe portion at downstream thereof and at the opposite end to the diffuser. The second pipe portion is disposed to extend adjacent to the exhaust manifold and made integral therewith in a rigid assembly, with the first pipe portion being releasably secured to the exhasut manifold and second portion through bolts for easy disassembly in servicing.

Abstract: A compression release device for side-valve and overhead-valve internal combustion engines is disclosed, which takes advantages of the difference in thermal expansion of different materials to control the valve opening depending on the condition of ambient temperature. A first material of comparatively higher linear expansion coefficient is used for the cylinders and cylinder head, while a second material of comparatively lower expansion coefficient for the push rods and tappets for either or both of the intake and exhaust valves, with the valve or valves being set to take a valve lift enough to cause the valve, upon compression stroke, to remain properly slightly open at cold start to ease crankshaft rotation, while stay fully shut, as a result of the cylinders and cylinder head having undergone a greater degree of thermal expansion than the push rods and tappets, when the engine gets warmed up.

Abstract: A valve gear adapted for a four-cycle engine having a guide portion formed on the outer surface of an output shaft connected to a crankshaft, and of such a shape folding around the output shaft as to return back to a starting point in two turns, and having interlocking mechanisms provided with portions engaging with the guide portion and moved by the rotation of the crankshaft to open valves. The guide portion, only one in number, is provided on the output shaft connected to the crankshaft, and the interlocking mechanisms for driving intake and exhaust valves are disposed substantially opposite to each other across the output shaft as to engage with aforesaid single guide portion.

Abstract: An overhead valve engine including a bore for receiving a push rod for actuating a suction valve and a bore for receiving a push rod for actuating a discharge valve. Blowby gas is introduced into one of the bores from a crank chamber and supplied to the other bore via a rocker arm chamber to lubricate the push rods with oil mist in the blowby gas. After lubricating the push rods, the blowby gas is released via the breather gas from the engine.

Abstract: A throttle control device for the general purpose engine having a throttle lever for moving a throttle valve of the carburetor and a choke lever for moving a choke valve of the carburetor. The choke lever and the throttle lever are moved together with each other in a predetermined timing. A control panel pivotally supporting the throttle lever and the choke lever is swingable in a predetermined angle range.

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: 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.