1970's 206? You can't have replaced the engine w/o Propellor r/r, so what's the story on the propellor? T/O with "rated" thrust in a Cessna 206 is not advised. Push in the Prop knob all the way? Seriously, without some data on the Prop, no sensible answers will appear. (How did you ever get off the ground with a mere 2200?).
bear