you should slowly increase temp by leaning the top end needle (clockwise) until it reaches it's maximum power output, between 220 - 260 F, leaning a little more at each iteration. When it reaches top power then you richen it again slightly (counter-clockwise) so you don't risk burning it out. The proper temp will vary by engine and weather. You probably shouldn't worry unless it gets over 280. 300 degrees and you are well into the danger zone.
Someone correct me if I'm wrong.