An engine assembly includes an engine, an external oil reservoir, a supply pump, and a return pump. The engine includes an oil gallery configured to distribute oil and a crankcase chamber. The external oil reservoir includes an oil tank defining an oil chamber and an oil filter assembly including a housing at least partially defining a filter chamber, and a filter positioned within the filter chamber. The supply pump is in fluid communication with the oil chamber and the oil gallery and the supply pump is configured to draw oil from the oil chamber and provide pressurized oil to the oil gallery. The return pump in fluid communication with the crankcase chamber and the filter chamber and the return pump is configured to draw oil from the crankcase chamber and provide pressurized oil to the filter chamber.

A cover of an internal combustion engine includes a cover body to be mounted to a crankcase of the internal combustion engine. The cover body includes a through hole, a protruding part, and a plurality of first recessed grooves. The through hole is to support a shaft rotatably. The protruding part is provided above the through hole in an upward direction of the internal combustion engine and protrudes toward an inside of the cover body facing the crankcase. The protruding part includes a first upper part and a first lower part in the upward direction on an inner surface of the protruding part facing the crankcase. The plurality of first recessed grooves extend radially from the through hole so as to connect the upper part and the lower part of the protruding part.

A small air-cooled internal combustion engine includes an aluminum cylinder block, an aluminum cylinder head welded to the aluminum cylinder block, and a weld securing the aluminum cylinder block to the aluminum cylinder head, wherein a joint having a first length is formed between the aluminum cylinder block and the aluminum cylinder head and wherein the weld extends for a second length that is at least 25% of the first length.

An internal combustion engine has a crankcase having a first crankcase portion fastened to a second crankcase portion along a first plane, a crankshaft, a cylinder block defining two cylinders, two pistons, and a cylinder head. A crankshaft support defines a crankshaft support aperture. A central portion of the crankshaft is received in the crankshaft support aperture. At least one fastener fastens the crankshaft support to the cylinder block. The at least one fastener is perpendicular to a crankshaft axis and is disposed in a second plane. The crankshaft axis is normal to the first plane. The second plane is one of coplanar with and parallel to the first plane.

An engine assembly includes a small air-cooled engine and a dry sump lubrication system including an external oil reservoir, wherein the dry sump lubrication system has an overall oil capacity that provides at least five hundred hours of engine oil life.