Sounds like the low-end is too rich. If it is "sluggish" when you advance the throttle it is rich if it just dies while idling it is lean- Go clockwise 1/8th of a turn at a time on the Low SPeed needle. (It is inside the throttle arm and you can usea small flathead screwdriver for that..)It is common for an engine with low time to needle the low speed reset once it starts to break in-- and a little dark oil is fine

Ideally you should be able to let it idle for 5 minutes (exagerration) 30 seconds is what I do- and when you advance the throttle quickly the engine should respond without being sluggish...