Try this,
http://www.modelflight.com.au/os-engines.htm
Or this,
http://manuals.hobbico.com/osm/61sx-...-wc-manual.pdf
High Speed needle-valve:
exactly two turns open from the fully closed position.(Note: If a different muffler is used, this setting may require readjustment)
Idle Mixture Control Screw:
exactly two turns open from the fully closed position.
Medium Speed needle-valve:
exactly one turns open from the fully closed position.