CDI Electronics Outboard Ignition Troubleshooting Guide

107 Mercury Troubleshooting Mercury 7. 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. 8. 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. Disconnect the idle stabilizer (advance module) and reset the timing between 23-25 degrees Wide Open Throttle. If the problem clears, discard the idle stabilizer as it is not needed. 3. 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. 4. 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 OR MORE CYLINDERS above). 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. 7. Rotate the stator one bolt hole in either direction and retest. FUEL INJECTORS NOT ACTIVATING: 1. Check the DVA voltage on the Green, Green/White and Green/Red wires, reference to engine ground at cranking speed. You should read at least 150 volts. If one wire reads low, it will affect 2 fuel injectors. 2. Check the voltage going to the fuel injectors, you should read above 10 volts while cranking the engine. 3. Check the DVA voltage across the fuel injectors, if you see approximately 25-60 volts, the injectors are pulsing. The injectors may be stopped up, possibly the inlet screen filters. FUEL PUMP NOT ACTIVATING: 1. Check the voltage going to the fuel pump on the Red wire, you should read above 10 volts while cranking the engine. 2. If the voltage is correct going to the fuel pump, connect a jumper wire to the Negative side of the fuel pump and touch it to engine ground. If the pump starts running, measure the amperage from the Negative side of the fuel pump to engine ground. The amperage should not be over 5 amps. If it is, the pump is likely defective and may have damaged the EFI. 3. Disconnect the 16 pin connector going to the EFI and jumper pin 2 to pin 16. If the fuel pump starts running, the circuit is OK and the problem lies elsewhere. 4. If the fuel pump runs when jumped but not when connected to the EFI, check pisn 6 and 7 for 12V at keyswitch on in the harness that connects to the EFi. If only one has 12V there is a problem in the harness or keyswitch.