Underperforming Continental 0-200
I wonder if I could pick the brains of the board about a C150 that I bought a few months ago. It's a nice little bird, and on the whole I like it a lot. But the engine does seem a little "odd" in two respects:-
1. It is really lacking in oomph. According to the book, I should be able to run it up on the ground to a minimum of 2,510 rpm. In fact I'm getting a max of 2,300 rpm, with correspondingly anaemic takeoff and climb performance, even by the less-than-exciting standards of C150s generally. I'd suspect it of having a cruise prop, but inasmuch as a 2,500 rpm cruise (it will eventually turn at that rate once in flight) only corresponds to around 82 kt TAS in still air, I don't think it can be that. Compressions are good -- mid-70s on all four cylinders, and oil burn within tolerances. I'm at something of a loss to explain this.
2. While in the air it vibrates like an East German tractor. One can see the pitot head and compass ball thrumming back and forth several hundred times a minute. Again, this seems much worse than in any of the many other C150s I've flown. According to the log, though, the prop was removed and balanced only eleven months ago. Hence I'd have thought it unlikely that that's the cause (not impossible, of course).
What do you think? Is this simply the consequence of having a fairly high-time engine (1,400 hours since the last major overhaul) and I should live with it? Or does either condition -- or both -- warrant a mechanic's investigation?