A small four-stroke engine capable of all positional operation has been developed. The engine for hand held equipment provides easy maneuverability like two-stroke engines which are dominated in the small engine market. The developed technologies include the following items. ①360° all positional operation by adopting a new lubrication system. ②Light-weight with a thin uni-block cylinder, etc. ③Normal operation at more than 10,000 rpm and at low and medium revolution range are combined by high output with a wide torque band. Equally easy handling and better workability compared with the conventional two-stroke engines are achieved. In addition, better starting reliability, drastically improved emission, and half-reduction of running costs are also confirmed.