Cylinder Trigger Circuit - Mercury 40 Service Manual

#1 Cylinder Trigger Circuit

The TRIGGER assembly (also mounted under the
flywheel) has one coil for each cylinder. These coils
are mounted adjacent to the flywheel center hub.
The center hub of the flywheel contains a permanent
magnet with two north–south transitions.
As the flywheel rotates, the magnet north–south tran-
sitions pass the trigger coils. This causes the trigger
CAPACITOR-
COIL-
SCR-
DIODE-
a - Battery Charging Coils
b - Trigger Coils
c - Capacitor Charge Coils
d - CDM #1
e - CDM #2
2A-10 - ELECTRICAL
a
S
N
N
S
3
+
_
_ N S
1
+
+
2
_
N
S
N
S
j
YEL
YEL
BLK
BRN
Return Voltage
Source Voltage
coils to produce a voltage pulse which is sent to the
respective capacitor discharge module (CDM). A
positive voltage pulse (N–S) will activate the elec-
tronic switch (SCR) inside the capacitor discharge
module (CDM). The switch discharges the capacitor
voltage through the coil primary windings. The return
voltage pulse exits the CDM through the ground wire
and returns through the trigger ground.
b
S
N
S
N
c
WHT/GRN
GRN/WHT
WHT
i
BLK/YEL
f - CDM #3
g - Rev. Limiter (Not Used On All Models)
h - To Ignition Switch
i - Stop Switch
j - To Voltage Regulator
d
e
f
PPL
g
BLK
h
90-852572R1 JANUARY 1998