CDI Electronics Outboard Ignition Troubleshooting Guide

92 TROUBLESHOOTING GUIDE - Mercury Troubleshooting Mercury Troubleshooting 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. (#) This reading can be used to determine if a pack has a problem in the triggering circuit. For instance, if you have no spark on one cylinder 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 pack is bad. 6. Inspect the ignition coils. You should have either a Red, Orange or Green coil with a bare braided ground wire from the backside of the coil. This bare braided ground wire MUST be connected to a clean engine ground. You cannot use a Black or Blue ignition coil. 7. Check the ignition coils as follows: Check resistance from + to – terminal reading should be 0.2-1.0 ohms and 800-1100 ohms from the high tension lead to engine ground. There should be no connection from the – terminal to engine ground. 8. Check the center hub triggering magnet in the flywheel. A loose magnet can cause this problem. 9. Check the triggering and charge coil flywheel magnets for cracked, broken and loose magnets. ENGINE HAS SPARK BUT WILL NOT RUN: 1. Index the flywheel and check the timing. If it is out by 180 degrees, swap the trigger wires to the switch box. 2. If the timing is off by any other degree, check the flywheel key. NO SPARK OR INTERMITTENT SPARK ON ONE CYLINDER: 1. Check the DVA output between the Green and Green/White wires from the switch box, also between the Blue and Blue/White wires while they are connected to the ignition coils. You should have a reading of at least 150V or more. If the reading is low on one cylinder, disconnect the wires from the ignition coil for that cylinder and reconnect them to a load resistor. Retest. If the reading is now ok, the ignition coil is likely bad. A continued low reading indicates a bad switch box. 2. Connect an inductive tachometer to each cylinder and compare the RPM readings at the RPM where the problem is occurring. If only one cylinder is dropping out, swap the ignition coil locations and retest. If the problem follows a coil, replace the coil. If it stays on the same spark plug, replace the switch box. 3. Disconnect the negative side of the ignition coils. Connect a jumper wire to the negative side of the coil and while the engine is turning over, tap the jumper wire to engine ground. If this causes the coil to spark, the coil is good and you will need to replace the pack. 4. Check the triggering and charge coil flywheel magnets for cracked, broken and loose magnets. 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 ON ANY CYLINDER above). 3. Replace the ignition coil on the cylinder dropping spark. 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 ON ANY 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. 6. Rotate the stator one bolt hole in either direction and retest.