CDI Electronics Outboard Ignition Troubleshooting Guide

117 Mercury Troubleshooting Mercury 3. Check the Throttle Position Sensor and the Engine Temperature Sensor. 4. Check the ECU. TIMING WILL NOT ADVANCE: Service Note: If timing will not advance on only one cylinder, check wiring between Ignition Module and ECU. If wiring is OK, replace Ignition Module. 1. Check the Crank Position Sensor and the Throttle Position Sensor. 2. Check the ECU. ENGINE MISSES AT HIGH RPM: 1. Check the Ignition Modules. 2. Check the Crank Position Sensor. 3. Check the Alternator’s Red output lead for tightness. 4. Check the ECU. 5. Check for correct spark plugs (use Champion QL77CC). ENGINE HARD TO START WHEN COLD: 1. Check the Enrichment Solenoid (Carbureted engines). 2. Check the Engine Temperature Sensor and the Crank Position Sensor. 3. Check the ECU. 4. Check the Harness for loose connections between ECU and Starter Solenoid. ENGINE MISSES @ LOW RPM, BUT RUNS SMOOTH @ HIGH RPM: 1. Check the Harness for loose connections between ECU and Ignition Modules. 2. Check the Ignition Modules. ENGINE STARTS HARD WHEN HOT: 1. Check the Enrichment Solenoid (Carbureted engines). 2. Check the Engine Temperature Sensor and the Crank Position Sensor. ENGINE WILL NOT RUN OVER 3000 RPM AND IS NOT OVERHEATING: 1. Check the Engine Temperature Sensor and the Throttle Position Sensor. 2. Check the ECU, Map Sensor and Shift Interrupt Switch.