CDI Electronics Outboard Ignition Troubleshooting Guide

113 Mercury Troubleshooting Mercury Six Cylinder Engines 1996-2005 2.5 L Engines Using CDM Modules NO SPARK ON ANY CYLINDER: 1. Cut each Black/Yellow stop wire from each CDM module and disconnect the RPM Limiter’s stop wire one at a time and retest. If the engine’s ignition sparks, the stop circuit you just cut has a fault. Check the key switch, harness and shift switch. 2. Disconnect the Yellow wires from the rectifier and retest. If the engine has spark, replace the rectifier. 3. Disconnect the ICM and reconnect the trigger to the CDM harness. If the engine has spark, verify 12V DC on the Purple wire to the ICM. If 12V DC is present, the ICM is faulty. If 12V DC is not present, check the key switch and harness. 4. Check the cranking RPM. A cranking speed of less than 250-RPM will not allow the system to spark properly. This can be caused by a weak battery, dragging starter, bad battery cables or a mechanical problem inside the engine. 5. Inspect the spark plug wires, boots and spark plugs. Check for chafing on the wiring and harnesses. 6. Inspect and clean all engine and ignition ground connections. 7. Pull on each wire from each CDM harness plug. Make sure all wires are making proper contact inside plugs. 8. Disconnect the CDM modules one at a time and see if you get spark back on the other cylinders. A shorted stop circuit in one CDM will prevent ALL cylinders from sparking. 9. Check the stator resistance and DVA output as given below: WIRE READ TO OEM RESISTANCE CDI RESISTANCE DVA (Connected) DVA(Disconnected) White/Green Green/White 380-430 380-430 160-400 V 200-400 V (*) (*) This reading can be used to determine if a stator or the CDM modules have a problem. For instance, if you have no spark on any cylinder and the stator’s DVA reading is low – disconnect the stator wires and recheck the DVA output. If the reading stays low – the stator is bad. If the reading is now within spec – at least one of the CDM modules is bad. 10. Check the resistance of each of the CDM modules as follows: RED METER LEAD BLACK METER LEAD READING CDM Pin # A C 1200-1400 Ohms CDM Pin # D A DIODE* CDM Pin # A D DIODE* CDM Pin # D B DIODE* CDM Pin # B D DIODE* CDM Pin # A B DIODE* High Tension Lead A OEM 700-1300 Ohms – CDI 2200-2400 Ohms * Diode readings are to be read one way, then reverse the leads and read again. You should get a low reading in one direction and a higher reading in the other. 11. Check the center hub triggering magnet in the flywheel. A loose magnet can cause this problem. 12. Check the triggering and charge coil flywheel magnets for cracked, broken and loose magnets. NO SPARK OR INTERMITTENT SPARK ON ONE OR MORE CYLINDERS: 1. Inspect the spark plug wires, boots and spark plugs. Check for chafing on the wiring and harnesses. 2. Clean and inspect CDM ground wire connections to engine ground. 3. Check the trigger resistance and DVA output as given below: WIRE READ TO OEM OHMS CDI OHMS DVA (Connected) DVA (Disconnected at Trigger) Purple Blue 1100-1400 850-1050 0.4 V + 4 V + (#) White Red 1100-1400 850-1050 0.4 V + 4 V + (#) Brown Yellow 1100-1400 850-1050 0.4 V + 4 V + (#) (#) This reading can be used to determine if a CDM has a problem in the triggering circuit. For instance, if you have no spark on one or two cylinders and the trigger’s DVA reading for that cylinder is low – disconnect the trigger wires and recheck the DVA output. If the reading stays low – the trigger is bad. If the reading is now within spec – the CDM is bad.