Agreed Islander.
I just find these threads very fustrating, as the two aircraft I fly don't have engine monitors.
One is fixed pitch (carb engine) and only engine gauges are rpm, oil temp & pressure. Other one is csp (fuel injected engine), and enginge gauges are MP, RPM, Oil pressure & temp, and single EGT.
Deakin who is always given as the great sage, says you can't use his advice because you don't have an engine monitor.
Everyone says you must lean, if you don't you'll fowl up the plugs.
But if you don't magically lean it correctly you'll damage the engine.
What is one to do? The POH isn't much help. It just says to lean, nothing more.
Seems like operating at low power settings is the only real safe way to operate the engine. Seems like a bit of a waste of an engine though, constantly using very low power settings.
All the advice that appears on pprune about engine leaning is geared to those with engine monitors, but unless I'm mistaken, most light aircraft don't have these. They tend to be the exception rather than the rule.
dp