Abstract: A cylinder body (2) is so formed as to project from a crank chamber (3) in an inclined manner, and a governor gear (50) for driving a centrifugal governor is arranged above a location where a crankshaft (20) is horizontally bridged within the crank chamber (3). An upper wall (71) of the crank chamber (3) is projected upwardly for accommodating the governor gear (50) within the crank chamber (3). An idle gear (45) is arranged at a location above the crankshaft (20) and below the cylinder (46) within the crank chamber (3), and the idle gear (45) is engaged with the crankshaft gear (42) and the governor gear (50) to transmit rotation of the crankshaft gear (42) to the governor gear (50).

Abstract: A loop-scavenged, two-cycle internal combustion engine has a low-pressure, cylinder wall fuel injection system that is practical for multi-cylinder marine engines and also reduces the amount of unburned hydrocarbons in exhaust emissions when compared to conventional carbureted two-cycle engines. The fuel injectors are mounted through the cylinder wall so that fuel spray contacts the piston crown underneath a zone in which incoming air flow through the transfer ports converges. The converging air flow helps to convect vaporized fuel from the piston crown upwards towards the spark plug electrode in the combustion chamber and away from the exhaust port, thereby reducing the likelihood of short circuiting unburned fuel through the exhaust port before the exhaust port closes and compression begins. All fuel is injected into the piston cavity before the exhaust port closes.

Abstract: An engine has an exhaust manifold placed on an air outlet side thereof, and an auxiliary device and a water pump are both positioned on the air outlet side of the engine toward one axial end of a crankshaft. The auxiliary device and the water pump are situated respectively at under and upper portions of the engine. At least one exhaust port as located on one side of the engine at one axial end of the crankshaft is positioned offset relative to the other side of the engine toward the other axial end thereof, thereby forming an enlarged void space in the engine between the water pump and the exhaust manifold. A thermostat case portion for a thermostat is placed in the void space.

Abstract: A fuel enrichment system for a multi-cylinder engine having a manifold balance line to deliver fuel to each of the cylinders as needed includes a valve located adjacent one of the carburetors to supply additional air/fuel mixture to approximately the center of the fuel balance line during the start-up of the engine.