CDI Electronics Outboard Ignition Troubleshooting Guide

134 TROUBLESHOOTING GUIDE - Yamaha Troubleshooting Yamaha Troubleshooting 25 HP (2 CYL) 1984-1987 30 HP (2 Cyl) 1984-1986 C30 HP (2 Cyl) 1989-1992 689-85540-21-00 NO SPARK: 1. Disconnect the White stop wire and retest. If the ignition system now has spark, the stop circuit has a problem. 2. Inspect and clean all engine and ignition ground connections. 3. Check the resistance of the ignition coil. Check From: Check To: Ohms Reading: Spark Plug Cap 1 Spark Plug Cap 2 2.8K (2800) to 4.2K (4200) 4. Check the Resistance and DVA Voltage of the CDI, Stator and Triggers as follows: Check From: Check To: Ohms Reading: DVA Reading: White/Red Black 12 to 16 5 V @ cranking Brown (Charge Coil) Black 120 to 160 190 V @ cranking Black/White Black (Eng Gnd) 0.18 to 0.24 210 V @ cranking HAS SPARK BUT WILL NOT RUN: 1. Make sure the engine is getting fuel to the combustion chamber (make sure there is no water or residue in the carburetor). 2. Check flywheel shear key to make sure it has not sheared due to backfiring or impact on the propeller. 3. Check flywheel magnet to make sure it has not broken loose and moved, causing a timing shift. 4. Check spark plug for presence of water, indicating a possible cracked block or blown head gasket. 5. Check compression, carburetor, reeds and do a cylinder leak down test. 6. Check the Triggers as follows as a defective trigger can cause timing variance: Check From: Check To: Ohms Reading: DVA Reading White/Red Black 12 to 16 5 V @ cranking NO SPARK OR INTERMITTENT ON ONE CYLINDER: 1. Check the resistance of the trigger and ignition coil. Check From: Check To: Ohms Reading: DVA Reading White/Red (Trigger) Black 12 to 16 5 V @ cranking Coil Lead #1 Coil Lead #2 2.56K-4.2K 2. Check the flywheel magnets for loose or broken magnets. 3. Replace the ignition coil. ENGINE WILL NOT ACCELERATE ABOVE APPROXIMATELY 2500 RPM: 1. Using an inductive tachometer, check the RPM on both cylinders. A difference in readings between the individual cylinders can be caused by a bad coil or loose/broken magnets. 2. If both cylinders show the same RPM and the engine will only rev to approximately 2500 RPM, check the running stator DVA output from idle thru WOT. You should show a steady increase in voltage on the Blue to engine ground through approximately 2000 RPM, then slowly decreasing the remainder of the RPM range. A sharp drop in voltage can be the result of a bad stator coil or a bad pack. WILL NOT STOP (KILL): Short the White wire from the CD Module to engine ground. If the engine stops, the problem is in the stop circuit. If the engine continues to run with the White wire shorted to engine ground, replace the defective CD Module.