CDI Electronics Outboard Ignition Troubleshooting Guide

105 Mercury Troubleshooting Mercury voltage right before the miss becomes apparent, the stator is likely at fault. 3. Check DVA voltage on the Red wires reference to engine ground of the stator at high speed. NOTICE: Use caution when doing this and do not exceed the rated voltage range of your meter. The readings should show a smooth climb in voltage. If there is a sudden or fast drop in voltage right before the miss becomes apparent, the stator is usually at fault. If there is no indication of the problem, it could be mechanical problem. 4. Rotate the stator one bolt hole in either direction and re-test. If the miss is gone, leave the stator as is. If the miss is worse, rotate the stator back where it was. 5. Using extreme caution, on the water or connected to a dyno, take the engine to the RPM where the problem is occurring and hold it for a few seconds, then perform a high speed shutdown at that RPM. Check the sparkplugs for differences in color or the presence of water droplets on the sparkplug (an indicator of a possible crack in the engine block). NO SPARK WITH THE SPARKPLUGS INSTALLED: 1. Check for dragging starter or low battery causing slow cranking speed. DVA test stator and trigger. 2. Disconnect rectifier, regulator and retest. If the problem goes away, replace the rectifier and/or regulator. SPARK ON ALL CYLINDERS BUT ENGINE WILL NOT RUN: Disconnect the White/Black wire and check the bias circuit (White/Black terminals) resistance to engine ground. Readings should be approximately 15,000W for standard packs. If the readings are correct on the packs, index the flywheel and check timing on all individual cylinders. If the timing varies, replace BOTH packs. DESTROYED ONE OR TWO CYLINDERS/PISTONS: 1. Check Bias resistance, from the White/Black stud to engine ground, you should read 13,000-15,000 ohms. Readings above 15,000 ohms or less than 13,000 ohms indicate a defective switchbox. Due to the design of the switchboxes, a switchbox with a defective bias circuit will damage a mating switchbox (domino effect). REPLACE BOTH SWITCHBOXES AS A SET!!!! 2. Use an ANALOG DC Voltmeter to check the voltage on the White/Black (Bias) terminal. With everything connected, run the engine at various Rpm’s and watch the voltage reading. It should remain steady for a set RPM. Fluctuation in voltage indicates a problem in the bias circuit. If there is a problem, disconnect everything on the White/Black terminal except the jumper from the inside switchbox to the outside switchbox. Retest, if the problem persists, replace BOTH switch boxes. If the problem went away, reconnect the items taken off of the White/Black terminal one at a time, retest after every reconnection until you locate the source of the problem. OVER-CHARGING THE BATTERY: 1. Verify the cranking battery is not an AGM, Maintenance free or Gel Cell battery. It needs to be a traditional flooded cell battery. 2. Verify the regulator has not been removed from the engine. If so, replace the rectifier with a regulator/rectifier. 3. Swap the battery with a known good one. If no change, check the resistance of the Yellow wires to engine ground. It should read open. A short on one wire can cause over-charging. 40 Amp Battery Charging Systems WIRE READ TO OEM RESISTANCE CDI RESISTANCE DVA (Connected) DVA (Disconnected) Blue Engine GND 3200-4200 2100-2400 180-400 V 180-400 V (*) Blue/White Engine GND 3200-4200 2100-2400 180-400 V 80-400 V (*) Red Engine GND 90-140 28-32 25-100 V 25-100 V (*) Red/White Engine GND 90-140 28-32 25-100 V 25-100 V (*) (*) This reading can be used to determine if a stator or pack has a problem. For instance, if you have no spark on any cylinder and the stator’s DVA reading is low – disconnect the stator wires and recheck the DVA output. If the reading stays low – the stator is bad. If the reading is now within spec – the pack is bad. (NOTE) If both Blue wires read low, check the cranking RPM. It must be more than 250 RPM. 3. Check the DVA output on the Green wires from the switch box while connected to the ignition coils. Check the reading on the switch box terminal AND on the ignition coil terminal. You should have a reading of at least 150V or more at both terminals on all cylinders. If the reading is low on one bank and the stator voltage is good, the switch box is usually bad. 4. Check the cranking RPM. A cranking speed less than 250-RPM will not allow the system to spark properly.