Engine lubrication system

An engine lubrication system has an arrangement in which the base of a crankcase (2) is used to form an oil reservoir (30), and a part of an oil slinger (31) that is driven by a crankshaft (1) via a transmission system (33) is immersed in the oil within the oil reservoir. An oil pump (32) that is driven by the transmission system is immersed in the oil within the oil reservoir, and a discharge port (50) of the oil pump communicates with a lubricating-oil passage (66) within the crankshaft. It is thereby possible to provide an engine lubrication system based on a splash-type lubrication system while at the same time using a forced-type lubrication system, thus reducing the capacity of the oil pump and simplifying the drive system, and effectively suppressing an increase in the overall cost.