J.P. Instruments EDM 930 Primary Pilots Guide - Manual (Page 11)

For Your Safe Flight Page 6
Scanner® Display Basics
The EDM Scanner section is located in the lower left area of the screen.
It consists of a graphical display of EGT and CHT (and TIT if so
equipped) and a digital display that automatically scans the various
parameters. You can select Manual Mode by tapping
STEP to lock onto
the parameter of interest. To return to Automatic scan mode, tap LF
followed by tapping
STEP .
LeanFind Basics
Simply pre-lean, then tap
the
LF button (Lean Find)
and begin leaning. The
EDM will assist you in
finding the first cylinder
to peak. This example is for Rich of Peak. See page 20 for a more
detailed description of leaning.
1. Establish cruise at approximately 65 to 75% power and pre-lean the
mixture to 50°F estimated rich of peak EGT on any cylinder.
2. Wait about 30 seconds, then tap the LF button.
3. Begin leaning the mixture smoothly without stopping. Turn a vernier
about ¼ turn per second; retract a non-vernier or quadrant lever so
that EGT rises about 10°F per second.
4. Stop leaning when you see LEANEST for two seconds, followed
by—for example— EGT 1520 FF 13.8. The left number is the current
temperature of the first EGT to peak and the right number is the
current fuel flow.
5. Now tap the PEAK button to display the EGT difference from peak
which is very useful for setting desired degrees below peak. Note:
The value for EGT ROP will be a negative value which means
you’ve gone lean of peak by the time you stopped leaning the
mixture.
6. Slowly enrich the mixture noting that the EGT difference diminishes
as EGT climbs back to peak, followed by it going positive again.
Stop enriching at the desired EGT difference (such as
‘EGT 75’ ).
Note: Please refer to the engine manufacturer’s operating guide for