J.P. Instruments EDM 740 Pilots Guide - Manual (Page 26)

Page 26 Engine Data Management
Lean Find-Rich Of Peak Detection: Eventually, one cylinder will reach
peak before any of the other cylinders. The EDM will determine this
automatically. The EDM will indicate success in finding a peak by
displaying the word
LEANEST for two seconds and flashing the peaked
EGT column. The Scanner® Information Area will also display the
current value for the peaked EGT on the left, and the word
SET on the
right (or fuel flow value, if so equipped), for final adjustment of the
mixture. The peak EGT value encountered during leaning is remembered
by the EDM and can be displayed by holding the LF button during Lean
Find Mode.
Lean Find-Finalizing the Rich Of Peak Mixture: You may now
enrichen the mixture to operate at peak or continue enriching to a value
of your choice (typically between 50 to 100° rich of peak for best
power), consistent with the procedures defined in your aircraft and/or
engine manual. Note: tap LF to see the current difference from the peak
temperature. This is handy for finalizing mixture. Tapping STEP exits
the lean find mode and automatic scanning resumes.