LUBRICATION UNIT FOR FOUR CYCLE ENGINE

PROBLEM TO BE SOLVED: To make it possible to lubricate engine parts thoroughly regardless of the engine position by supplying lubricant to the valve compartment by the lubricant pump which is directly connected to the engine crankshaft, and by transforming the lubricant to a mist state to lubricate the valve unit and then the lubricating sliding/rotating parts in the crank compartment, and then returning the lubricant to the lubricant tank. SOLUTION: When an engine 1 is started by a recoil starter 12, a lubricant pump 15 is activated by rotation of a crankshaft 7 via a series of gears. The lubricant in a lubricant tank 39 is sucked and pressure-fed to a lubricant supply passage 29 which is connected to a valve compartment 24. Then, the lubricant is introduced into a lubricant supply passage 28 holed in a camshaft 25 that is rotated at a reduced speed within the valve compartment 24, and sprayed from an injection port 30 as oil mist for lubrication of a valve unit 22. When the pressure is reduced in a crank compartment 5 following the rise of a piston 9, lubricant in the valve compartment 24 is sucked into the crank compartment 5 via a passage 37 and a check valve 38 such that lubricant is supplied to the sliding parts, after which it is returned to the lubricant tank 39 via a return passage 42.