ORIGINAL: Sport_Pilot
I think the engine just needs to warm up. Engines need a richer mixture when cold because less fuel vaporizes and mix's with the air.
X2
When an engine is stone cold it will run lean. Even when an engine has cooled down between flights, most likely in direct sunlight, it is still not as cold as an engine that has sat idle, most likely in a shaded place for 24 hours or more.
What OP was experincing indicates that his tune is spot on. If it didn't exibit these syptoms, the tune would most likely be a bit on the rich side.
Nothing to be concerned about.