Four-stroke engine lubricated by fuel mixture

A four-stroke engine includes a piston cylinder, and a piston located in the cylinder and movable within the cylinder. The engine includes a crankcase attached to the cylinder, the piston providing a separation boundary of a combustion portion of the cylinder from the crank case, and a crank member located within the crankcase and operatively connected to the piston. The engine including components for operating the engine in a four-stroke sequence, and components for introducing a fuel mixture into the combustion portion of the cylinder, the fuel mixture having an ability to lubricate. The engine including a construction and/or configuration for promoting passage of a portion of the mixture from the combustion portion of the cylinder to the crankcase in a sufficient amount to provide lubrication within the crankcase without reservoir lubricant in the crankcase.