J.P. Instruments EDM-900

For Your Safe Flight ............................................. Page 29
Rich of Peak leaning is as simple as:
A. Pre-lean your mixture.
B. Tap the LF button (verify ROP appears).
C. Lean mixture until LEANEST flashes (peak found).
D. Enrichen to the desired value ‘Rich Of Peak’.
R
Procedure
Scanner
Example
Comments
1
Establish cruise at 65
to 75% power.
2
Pre-lean the mixture to
50°F estimated rich of
peak on any EGT:
_________°F.
EGT 1490
CHT 370
* See ‘Pre-leaning’ page 31.
3
Wait one minute
Let engine stabilize.
4
Tap the LF button
ROP
Start Lean Find (if LOP appears hold
STEP & LF until ROP appears)
5
Lean the mixture at
approx. 10°/second
without pausing.
EGT 1520
FF 13.8
Flashing cylinder I.D. box identifies that
EGT increased at least 15°F. EDM is
now looking for first EGT to peak.
6
Stop leaning when
a column begins
flashing. You will see
LEANEST for one
second, followed by:
EGT 1545
FF 12.4
Flashing cylinder I.D. box AND its
column indicates leanest cylinder. Due
to thermal inertia this will usually be
about -15°F down the lean side of peak.
7
If you hold PEAK, the
values of EGT and FF
when peak was found
are displayed.
EGT ↑1560
FF 12.9
Captured peak EGT value and peak FF
are displayed.
8
If you tap PEAK, the
difference from peak
EGT is shown. Tap
again to return to the
peaked EGT value.
EGT∆ -90
FF 13.4
A useful mode for setting mixture the
desired degrees rich of peak - no math
required! NOTE: Unit remembers view
last used.
9
Slowly enrich the
mixture noting that
EGT is returning to
peak. Stop enriching at
the desired EGT.
‘Peak’: best Econ.
‘ROP’ target: best
power.
EGT 1560
FF 12.9
EGT 1460
FF 13.6
(100º RICH OF
PEAK)
Rich of Peak target
leaner
richer
‘FF’
EGT
1560
Peak
-100
1460