"David Megginson" wrote in message
...
Note the original statement:

Specifically, you should not be leaning if your engine in making 75%
power or better.

There may be planes where it's not OK to lean at 75%, but all of the
POH's I've looked at so far *require* leaning at 75% power to get the
performance numbers (fuel burn and range) that they list.

http://www.avweb.com/news/columns/182152-1.html (Article 57, but read 58 &
59 as well).