Gasolene engines are designed to idle at a "higher than normal" speed when cold to reduce the possibility of them stalling - how fast does yours idle? I'd say around 1800 rpm when started and then dropping slowly as the engine warms is normal.
Depending on what carburettor you have, there may be a "fast" or "cold" idle adjustment - or if you have the Hitachi electronic feedback carb, I believe a vacuum leak can also cause it to idle fast.