Mercury 40 FourStroke - Recommended Test

IGNITION
90-857046R1 NOVEMBER 2001 Page 2A-15
*Recommended Test
(1) DVA TEST (Direct Voltage Adapter)
(2) OHM TEST (Resistance Testing)
(3) Replace Component and Retest
(4) Mechanical Test/Repair
PROBLEM/CONDITION
Probable Cause *Perform
Test No.
No Spark Condition (All Cylinders) Crank Position Sensor
Stator
(ECM)
Stop Circuit Short to Ground:
a - stop circuit lead
b - lanyard stop switch
c - tiller handle stop button (if supplied)
d - remote control harness
Ignition Coil
a - primary Circuit Shorted to Ground
Spark Plugs
Open Ground Condition:
a - ignition coil
b - stator ground
c - (ECM)
2
1-2
3
2
2
2
2
2
2
3
2
3
3
No Spark Condition (One Cylinder) High Tension Lead
Spark Plug Cap (Resistor)
Spark Plug
2
2
3
Weak Spark Condition Ground Connection at:
a - Ignition Coil Primary Leads
b - Stator
c - (ECM) Primary Coil Supply Leads
High Resistance To Ground at:
a - stop/lanyard switch (water/corrosion)
Weak Charge Coil
Ignition Coil/High Tension Lead(s)
Spark Plug(s)
Spark Plug Cap (Resistor)
Spark Plug Cap Leak
(ECM) Failure
2
2
3
2
1-2
1-3
2
3
3
3
Timing Fluctuates
NOTE: It is considered normal
for the timing to fluctuate approxi-
mately 1
° - 2 ° within the desig-
nated timing window.
Loss Of Oil Pressure/Over Heating:
a - timing retards and fluctuates, rpm
will drop below 2000 rpm
Flywheel Key Sheared
(ECM) Unit
4
4
3
Timing Will Not Advance Low Oil Pressure/Engine Over Heating:
a - timing retards and fluctuates, rpm
will remain below 2000 rpm
(ECM)
4
3