CDI Electronics Outboard Ignition Troubleshooting Guide

82 TROUBLESHOOTING GUIDE - Mercury Troubleshooting Mercury Troubleshooting Mercury Battery CD Ignitions GENERAL: 1. Clean all battery connections and engine grounds. 2. Disconnect the mercury tilt switch and retest. If the ignition works properly, replace or discard the mercury tilt switch. 3. Connect a spark gap tester to the spark plug wires and check for spark on all cylinders. If some cylinders spark and not others, the problem is likely in the distributor cap, rotor button or spark plug wires. 4. Perform a voltage drop test after the engine is repaired to see if there is a problem with the voltage going to the CD module. At cranking and while the engine is running, use a DC voltmeter and put the Black meter lead on the battery POS (+) post and the Red meter lead on the positive battery cable at the starter solenoid. Keep the Black lead on the battery post and shift the Red meter lead to the positive post of the rectifier, then to the Red and White terminals on the switch box. If you find a reading above 0.6V, there is a problem at the point where the voltage jumped up. For example, if the meter reads 0.4V until you get to the White terminal and then jumps to 2.3V on the White terminal – this indicates a problem in the key switch, or harness. Repeat the test for the negative battery post by putting the Black meter lead on the battery NEG (-) post and the Red meter lead on the negative battery cable terminal, then shifting to the engine block, rectifier base and case ground of the CD module. NO SPARK ON ANY CYLINDER: 1. If a mercury tilt switch is connected to the switch box, disconnect it and retest. If you now have spark, replace or discard the mercury tilt switch. 2. Check DC voltage on the White and Red terminals (White/Red wire on the 114-2986) (they must be connected to the switch box) to Engine Ground AT CRANKING. It MUST be at least 9.5 volts. If not, there is most likely a problem in the battery. Try a known-good non-maintenance-free cranking battery. If no change, check the key switch, starter and battery cables. 3. Perform the jumper wire test in the illustration above. Disconnect the trigger wires from the switch box and connect a jumper wire from the Brown trigger terminal/wire of the switch box to the White trigger terminal/wire of the switch box. Connect another jumper wire to the Black trigger terminal/wire of the switch box. Turn the ignition switch to ON. Strike the jumper wire from the Black trigger terminal/wire against Engine Ground – (DO NOT HOLD THE JUMPER AGAINST ENGINE GROUND). The ignition coil should spark each time the Black wire is tapped to Engine Ground. If not, the switch box and/or ignition coil is faulty. 4. Connect a spark gap tester to the high-tension lead coming from the ignition coil and set it to approximately 7/16”. When you crank the engine over, if it sparks while the spark gap tester is connected to the coil and does not spark through the spark plug wires – there is a problem in the distributor cap, rotor button or spark plug wires. 5. Check DC voltage on the Brown trigger terminal/wire (it must be connected to the switch box) to Engine Ground AT CRANKING. It must be at least at least 9V DC. A low reading indicates a bad switch box. 6. Check DVA voltage between the White and Black trigger terminals/wires (they must be connected to the switch box) AT CRANKING. It must be at least 3V DVA. A low reading indicates a bad trigger. 7. Check DVA voltage on the Green wire going to the coil to Engine Ground AT CRANKING. It must be at least 100V DVA on an OEM switchbox (200V on a CDI Electronics Switchbox). A low reading indicates a bad switch box. ONLY HAS SPARK AS LONG AS THE STARTER IS ENGAGED: This symptom usually indicates a bad trigger or low battery voltage. NO SPARK OR INTERMITTENT SPARK ON ONE CYLINDER: 1. Connect a spark gap tester to the high-tension leads coming from the distributor cap and set the gap to approximately 7/16”. (Use of a CD Tester is recommended). 2. Align the rotor with #1 spark plug wire. Disconnect the trigger wires from the switch box and connect a jumper wire from the Brown trigger terminal/wire of the switch box to the White trigger terminal/wire of the switch box. 3. Connect another jumper wire to the Black trigger terminal/wire of the switch box. Turn the ignition switch to ON. Strike the jumper wire from the Black trigger terminal/wire against Engine Ground – (DO NOT HOLD THE JUMPER AGAINST ENGINE GROUND). Only the #1 spark plug wire should spark. If any other spark plug wire has spark, there is a problem in the distributor cap. 4. Repeat the test for the other cylinders.