They have their drive output crankshaft emerging vertically from the bottom of the engine on which is usually mounted a blade, drive pulley, fan or clutch. A pull starter and/or a flywheel guard grill will be on the top of the engine.
The piston runs horizontally and the spark plug(s) will be located on the front of the engine.
Single cylinder, V Twin and Opposed(flat) Twin Vertical crankshaft engines have all been manufactured.
Vertical Engine Crankshaft Dimensions
To check crankshaft dimensions of a vertical crankshaft engine, place a straight edge against the end of the bare crankshaft (pulley or blade mount removed) and measure the height to the mounting face of the engine. The length of shaft emerging from the bottom of the engine is NOT the quoted length.