CDI Electronics Outboard Ignition Troubleshooting Guide

96 TROUBLESHOOTING GUIDE - Mercury Troubleshooting Mercury Troubleshooting 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 flywheel magnets for cracked, broken and loose magnets. Two Cylinder Engines 1994-1996 (With 114-4952A30/ 1 8495A9, A14, A16, A20, A21 or A30 Switch Box) (NOTE) This engine has a locked trigger arm. Therefore, the timing is controlled by the switch box and is adjusted according to the engine RPM. RPM limiting is done by retarding the timing at high RPM. NO SPARK ON EITHER CYLINDER: 1. Visually inspect the stator for cracks or varnish leakage. If found, replace the stator. 2. Disconnect the Black/Yellow kill wire FROM THE SWITCHBOX. If spark returns, the Kill circuit has a fault. 3. Check for broken or bare wires on the switchbox (including ground wires, stator and trigger. 4. Check the stator and trigger as follows: Read from Read to OEM Ohms CDI Ohms DVA Connected Disconnected Blue Stator wire Black Stator wire 2900-3500 2300-2750 180V or more 180V or more Red Stator wire Black Stator wire 100-180 200-250 25 V or more 25 V or more Black Stator wire Engine Ground -- -- 5 V < 1 V Brown/White Brown/Yellow 650-750 650-750 4 V or more 4 V or more Brown/White Eng Gnd OPEN OPEN < 1 V < 1 V Brown/Yellow Eng Gnd OPEN OPEN < 1 V < 1 V NO SPARK OR INTERMITTANT SPARK ON ONE CYLINDER: 1. Inspect the flywheel to see if one of the magnets has broken loose and shifted around to where it is touching the other magnet. 2. Connect a spark tester to the ignition coils and swap the Green wires on the switchbox to the ignition coils. If the problem moves, check the trigger wires for continuity. If OK, replace the switchbox. If the problem did not move, replace the ignition coil. 3. Verify the correct spark plugs are installed. OEM calls for a BP8H-N-10 or BPZ8H-N-10 (use the BPZ8H-N-10 is the engine has a miss-fire). ENGINE WILL NOT SHUT OFF: Check the kill circuit in the pack by using a jumper wire connected to the Black/Yellow wire coming out of the pack and shorting it to ground. If this kills the engine, the kill circuit in the harness or on the boat is defective, possibly the ignition switch. HIGH SPEED MISS: 1. Disconnect the Yellow wires to the rectifier/regulator and retest. If the miss is gone, replace the rectifier/regulator. 2. Check the DVA voltage of the stator from the Red wire to the Black wire while running the engine. It should show a smooth climb on the voltage. NOTICE: Use caution when doing this and do not exceed the rated voltage range of your meter. If there is a sudden or fast drop in voltage right before the miss becomes apparent, the stator is usually at fault. 3. Verify the correct spark plugs are installed. OEM calls for a BP8H-N-10 or BPZ8H-N-10. If the BP8H-N-10 spark plugs are installed, try the BPZ8H-N-10 spark plugs. 4. If there is no indication of the problem, it could be a small water leak in one or both cylinders. BOTH CYLINDERS HAVE SPARK BUT THE ENGINE WILL NOT RUN: 1. Check the flywheel shear key. 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. 3. If no other fault is found, replace the switch box.