Abstract: Two stroke engines of crankcase precompression type comprising an integral main body block which includes a cylinder block section and a crankcase upper section, and to which a crankcase lower section and a cylinder head are secured at the lower and upper ends thereof. The body block is formed with scavenging passages of which lower ends are substantially straight so as to facilitate removal of the block from manufacturing dies. The engine includes a crankshaft which is supported by bearings secured to the crankcase lower section by means of separate semi-circular retaining members.

Abstract: A sixty degree, V-6 engine for an outboard motor includes loop scavenging and charging with a pair of oppositely located input passageways with differently angles sidewalls and which provide progressive, smooth constriction to the charging port to establish a highly effective velocity pattern across the top of a flat piston. Cast "Blister" cylinder liners with integral ports are integrally cast into an aluminum block. The block is cast with a single manifold between the two cylinder blanks. A milling cutter is located within the manifold to open the exhaust passageways. A T-shaped manifold is secured to close the manifold and define a pair of separate exhaust passageways. The cylinders are rotated to align the upper and lower inlet ports and particularly to locate the exhaust port projecting downwardly into a center manifold. Adjacent piston rods are mounted upon a common crankshaft pin.

Abstract: Disclosed herein is an internal combustion engine comprising a piston movable relative to a cylinder and a crankcase between top dead center and bottom dead center positions and relative to first, second and third positions respectively spaced from top dead center position at respectively greater distances, whereby the crankcase is subject to cyclical conditions of relatively high and low pressure, a transfer chamber, a reed valve controlled port for supplying fresh air to the transfer chamber when the transfer chamber is subject to low pressure, a carburetor for supplying a fuel/air mixture to the crankcase when the crankcase is subject to low pressure, a transfor port providing communication between the transfer chamber and the crankcase during conditions of low pressure in the crankcase and during piston travel between top dead center position and the first position whereby to cause introduction into the transfer chamber of fresh air, whereby the air introduced into the chamber is isolated during piston mo

Abstract: A two-stroke internal combustion engine has a plurality of transfer ports controlled by the movement of the piston, the transfer ports being at the ends of passages each extending from the interior of the crankcase through the cylinder wall so as to place the crankcase interior in communication with the upper working space in the cylinder above the piston when its associated transfer port is uncovered by downward movement of the piston. Some, but not all, of the transfer port passages are provided with pressure-responsive non-return valves which are lightly spring-biassed towards closed positions in which they restrict the gas flow through those passages, in the direction towards the upper working space in the cylinder, causing the gas flow from the crankcase to travel at increased velocities through the remaining transfer port passage or passages.

Abstract: A two-cycle internal combustion engine having reed-type intake valving, and specially configured and positioned intake and injection porting, with the porting constructed and arranged to improve various of the operating characteristics of the engine.

Abstract: A two-cycle crankcase compression internal combustion engine having extended and specially positioned intake porting and reed-type intake valves, with the porting and valves arranged to improve various of the operating characteristics of the engine.

Abstract: Disclosed herein is an internal combustion engine (and a method of operation thereof) comprising a piston movable relative to a combustion chamber and to a crankcase to effect cyclical pressure variation in the crankcase in response to piston movement, a transfer passage for introducing fuel-air mixture into the combustion chamber from the crankcase in response to cyclical crankcase pressure variation, an auxiliary chamber separate from the transfer passage, and a port arrangement for providing the auxiliary chamber with pressurized air in response to cyclical crankcase pressure variation and for initiating communication of the auxiliary chamber with the combustion chamber in response to piston movement during the presence of pressurized air in the auxiliary chamber and at a time other than the time of initiation of introduction of fuel-air mixture into the combustion chamber.

Abstract: The invention provides a bypass around virtually the entire periphery of a piston in a two cycle engine without substantially increasing costs or obsoleting production tooling. This is done by reshaping a cavity formed inside an engine casting to enlarge the crank case opening and to provide three oppositely displaced bypasses. The fourth side of the piston is open to the exhaust port. Therefore, virtually the entire perimeter of the piston is bypassed to greatly increase power by improved breathing.

Abstract: The invention is an improved piston and cylinder arrangement for a loop charged two-stroke engine wherein all input passages are open channels in the cylinder wall and the top annular edge of the piston is rounded. The rounded edge on the piston cooperates with the described scavenging and input passages to reduce drag and, cause the incoming charge to flow more horizontally over the piston head; thereby improving scavenging and volumetric efficiency.