16
3. One ignition at a time: Turn bus power ON, Kill Switch ON, and (if installed) Mode Switch to
VAR. LED will be steady RED. Rotate the prop by hand in the normal direction of travel
and confirm all plug pairs fire in proper sequence. Any deviation indicates a wiring or setup
error
.
•
Both plugs for cylinders 1&2 (Bank A) fire at the starting lag position (4 degrees after
TC).
•
Both plugs for Bank B fire 120 degrees later
– see Note 3
.
•
Both plugs for Bank C fire 240 degrees later
– see Note 3
.
Note 1: Plugs will not fire:
i) When the engine is rotated the wrong direction.
ii) If ignition DIR is not configured to match engine rotation.
iii) When Mode Switch is in FIX position and engine is moving at hand pull-thru speeds.
iv) Plugs fire only once per cycle. You cannot back up and fire them again. Keep pulling thru
in the normal direction.
Note 2: Multi-Strike. At cranking speeds, the ignition uses a (5) rapid strike sequence for each
bank. This means the Pull-
Thu Test will not produce the familiar single spark “click”. Instead, you’ll
hear the plugs “buzz” - the sound of a multi-strike sequence.
Note3: Due to the variety of engine and ignition configurations, it may be necessary to swap the
plug wire to cylinder (Banks B and C) assignments to achieve proper firing
– per the engine
manufacturer firing order.
Note 4: Pull-Thru firing positions cannot be used to verify ignition tracking accuracy. It only confirms
proper wiring and circuit assignments.
Tuning MAX
Orientation:
Operating the ignition in Variable Mode (Mode
Switch “VAR”) can improve engine efficiency by
enabling automatic adjustment of the plug firing advance. The range of automatic adjustment is
capped by the MAX setting. MAX will be either the default (9-degrees ahead), or a lesser MAX
position (as low as 6-degrees ahead) as set
by the operator.
TIP: Most Cont 550 customers are reporting improved cruise performance with MAX setting
reduced to 6-degrees ahead of MIN (vs. the 9-degree default).
Operators can monitor VAR mode cruise conditions (RPM above 2400
and MAP 22” or below)
where spark advance is greatest and be
mindful of the engine manufacturer
’s temperature
recommendations and red-lines. It should be understood that improving efficiency (extracting more
energy from a given amount of fuel) means a certain amount of additional heat may be generated.
