Leanfind procedure—step-by-step, For your safe flight page 15 – J.P. Instruments EDM 760 Pilots Guide User Manual

Page 19

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LeanFind Procedure—Step-by-Step

Procedure

Example

Comments

1

Establish cruise at approx.
65 to 75% power.

2

Pre-lean the mixture to 50°F
on the rich side of the
estimated peak EGT on any
cylinder: _____°

I490
370

*For your first flight with the
EDM-760, use the method
shown below.

3

Wait one minute

Let engine stabilize.

4

Tap the LF button

I490
LF

Start the LeanFind mode.

5

Slowly lean the mixture—
approx. 4°/second—while
observing the display. When
there is a 15°F rise in EGT,
LeanFind mode becomes
active.

I520
LF
(Fuel Flow
Option
shows
flow)

Flashing cylinder number
indicates hottest cylinder and
that LeanFind mode is active.

6

Stop leaning when
a column begins flashing.
You will see

PEAK EGT for

two seconds, followed by:

I550
SET

or with
Fuel Flow
I550
I 2.4

Flashing cylinder number &
column indicates leanest
cylinder. (SET means that
the peaked cylinder is “set”
into the display.) Due to
thermal inertia this will
usually be about 10°F lean of
peak.

7

If you hold LF, peak EGT will
be displayed while the LF
button is held down.

I560
PEAK

Captured peak EGT value is
displayed.

8

Slowly enrich the mixture. the
temperature will increase,
returning to peak.
Stop enriching at the desired
EGT.

Best economy

Best power

I560 SET

I560 SET
I460 SET

Peak EGT for best
economy

100° cooler than peak for
best power

Best

power

Temperature when

column flashes

best economy

leaner

richer

*Here is how to determine the pre-lean value: while in cruise at under 65
percent power, choose any cylinder and lean that cylinder to peak EGT in
the Manual indexing mode or to engine roughness, whichever occurs first.
Note the peak, subtract 50° and write the resulting number in the space
provided in step 2.

For Your Safe Flight

Page 15

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