Engine generator

A positioning pin (15) is knocked onto a crankshaft (14) of an engine and a key way (26a) is formed in a boss of a first flywheel (25). When an outer rotor (21) type generator is connected with the engine, the boss (26) of the first flywheel (25) is fitted over the crankshaft (14) so as to adjust the positioning pin (15) to the key way. When an inner rotor (41) type generator is connected with the engine, a rotor shaft (46) on which a rotor of a generator is mounted is fitted to a second flywheel (48) so as to adjust the positioning pin (15) to a key way formed in the second flywheel (48). The ignition angle of the engine is determined by fitting the positioning pin to the key way.