CDI Electronics Outboard Ignition Troubleshooting Guide

97 Mercury Troubleshooting Mercury ENGINE LOW ON POWER OR TIMING WILL NOT ADVANCE WITH ENGINE RPM: 1. Verify the ignition timing is advancing from about 5 degrees BTDC at idle to approximately 28 degrees BTDC at 3000 RPM. NOTE: The timing will retard slightly from 28 degrees BTDC at 3000 RPM to 25 degrees BTDC at 5500 RPM, dropping down to 15 Degrees BTDC between 5800 to 6200 RPM. 2. Index the flywheel and check timing on both cylinders. If the timing is off, check the trigger and flywheel. NOTE: If one of the trigger wires is shorted, the timing may not advance on ONE cylinder, but the other cylinder will advance. SWITCH BOX OR TRIGGER REPEATEDLY BLOWS ON SAME CYLINDER: 1. Check the trigger wires for shorts to engine ground as a shorted trigger wire can destroy a SCR inside the switch box. 2. In contrast, a shorted SCR inside the switch box can destroy a trigger coil. Check the trigger resistance and DVA output (see NO SPARK OR INTERMITTENT SPARK ON ONE CYLINDER above). 3. Replace the ignition coil on the cylinder dropping spark. WILL NOT ACCELERATE BEYOND 3000-4000 RPM: 1. Disconnect the Yellow wires from the stator to the rectifier and retest. If the engine now has good spark, replace the rectifier. 2. Connect a DVA meter between the stator’s Blue and Black wires. Run the engine up to the RPM where the problem is occurring. DVA voltage should increase with RPM. A sharp drop in DVA right before the problem occurs usually indicates a bad stator. 3. Connect a DVA meter between the stator’s Red and Black wires. The DVA voltage should show a smooth climb in voltage and remain high through the RPM range. A reading lower than on the Blue wire reading indicates a bad stator. 4. Connect an inductive tachometer to each cylinder in turn and try to isolate the problem. A single cylinder dropping spark will likely be a bad switch box or ignition coil. All cylinders not sparking properly usually indicates a bad stator. 5. 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. 6. Check the triggering and charge coil flywheel magnets for cracked, broken and loose magnets. MISS AT ANY RPM: 1. Disconnect the Yellow wires from the stator to the rectifier and retest. If the miss clears, replace the rectifier. 2. 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. 3. 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). 4. 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. 5. Check the triggering and charge coil flywheel magnets for cracked, broken and loose magnets. Two Cylinder Engines 1994-2006 (With 114-5713/ 8 55713A3 & A4 Switch Box) NO SPARK ON ANY CYLINDER: 1. Disconnect the Black/Yellow 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. 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. 3. Inspect and clean all engine and ignition ground connections.