CDI Electronics Outboard Ignition Troubleshooting Guide

99 Mercury Troubleshooting Mercury MISS AT ANY RPM: 1. In the water or on a Dynameters, check the DVA output on the Green wires from the switch box while connected to the ignition coils. You should have a reading of at least 150V DVA or more, increasing with engine RPM until it reaches 300-400V DVA maximum. A sharp drop in DVA right before the miss becomes apparent on all cylinders will normally be caused by a bad stator. A sharp drop in DVA on less than all cylinders will normally be the switch box or trigger. 2. Connect an inductive tachometer to each cylinder in turn and try to isolate the problem. A high variance in RPM on one cylinder usually indicates a problem in the switch box or ignition coil. Occasionally a trigger will cause this same problem. Check the trigger DVA voltage (see NO SPARK OR INTERMITTENT SPARK ON ONE CYLINDER above). 3. Perform a high-speed shutdown and read the spark plugs. Check for water. A crack in the block can cause a miss at high speed when the water pressure gets high, but a normal shutdown will mask the problem. 4. Check the triggering and charge coil flywheel magnets for cracked, broken and loose magnets. Three Cylinder Engines 1976-1996 Three Cylinder Engines Using a Single Switch Box and Three Ignition Coils NO SPARK ON ANY CYLINDER: 1. Disconnect the Black/Yellow (or Orange) stop wire AT THE SWITCH BOX and retest. If the engine’s ignition now has spark, the stop circuit has a fault. Check the key switch, harness and shift switch. 2. Disconnect the Yellow wires from the stator to the rectifier and retest. If the engine has spark, replace the rectifier. 3. Check the cranking RPM. A low cranking speed may 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. 4. Inspect and clean all engine and ignition ground connections. 5. Check the stator resistance and DVA output as given below: Black Stator using Flywheel with Bolted-in Magnets WIRE READ TO OEM OHMS CDI OHMS DVA (Connected) DVA (Disconnected) Blue Engine GND 5800-7000 2000-2400 180-400 V 180-400 V (*) Red Engine GND 135-165 45-55 25-100 V 25-100 V (*) Black Stator using Flywheel with Glued-in Magnets WIRE READ TO OEM OHMS CDI OHMS DVA (Connected) DVA (Disconnected) Blue Engine GND 3250-3650 488-662 180-400 V 180-400 V (*) Red Engine GND 75-90 28-32 25-100 V 25-100 V (*) Red Stator Kit WIRE READ TO OEM OHMS CDI OHMS DVA (Connected) DVA (Disconnected) White/Green Green/White 500-700 400-550 180-400 V 180-400 V (*) Blue Engine GND OPEN OPEN 180-400 V 180-400 V (*) (*) This reading can be used to determine if a stator or pack has 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 – the pack is bad. 6. Check the center hub triggering magnet in the flywheel. A loose magnet can cause this problem. 7. 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. Check the trigger resistance and DVA output as given below: WIRE READ TO RESISTANCE DVA (Connected) DVA (Disconnected) Brown White/Black (or Black) 800-1400 4 V + 4 V + (#) White White/Black (or Black) 800-1400 4 V + 4 V + (#) Purple White/Black (or Black) 800-1400 4 V + 4 V + (#) Brown Engine GND Open 1 V + N/A White Engine GND Open 1 V + N/A Purple Engine GND Open 1 V + N/A