Outboard Ignition Troubleshooting – Page 6 – Force Prestolite ADI Ignitions (1984-1992)
This section covers Force Prestolite ADI ignitions from 1984 through 1992. These procedures help diagnose no spark, intermittent spark, high-speed misses, kill circuit faults, and related stator, trigger, and rectifier issues.
Force Prestolite ADI Ignitions 1984-1992
General
- Check for broken wires and terminals, especially inside the plastic plug-in connectors. Remove the pins from the connectors and visually inspect them if needed.
- Check the flywheel for a broken or loose magnet.
- Disconnect the kill wires from the CD and connect a DC voltmeter between the kill wires and engine ground. Turn the ignition switch on and off several times. If voltage appears at any time, there is a problem in the harness or ignition switch. At NO TIME should battery voltage be present on a kill circuit.
- Visually inspect the stator for burned or discolored areas. If found, replace the stator. If the damage is on the battery charge windings, it indicates a possible problem with the rectifier.
If No Fire on Any Cylinder
- Disconnect the kill wire at the pack.
- Check for broken or bare wires on the unit, stator, and trigger.
- Measure DVA voltage of the stator between the output wire sets. With everything connected, readings should be approximately 180 volts or more. Resistance readings between the stator wire sets should range from 680 to 800 ohms.
- Disconnect the rectifier. If the engine fires, replace the rectifier.
No Fire or Intermittent on One Cylinder
- Check stator and trigger resistance. Trigger wire sets should read approximately 50 ohms between the wire sets (DVA 5V or more). Stator should read 680–800 ohms, DVA 180V or more from blue to yellow.
- If readings are good, disconnect the kill wire from one pack. If the dead cylinder starts firing, the problem is likely the blocking diode in the other pack.
No Fire on Two Cylinders
- If two cylinders from the same CD unit will not fire, the problem is usually in the stator. Test as described above.
Engine Will Not Kill
- Check the kill circuit in the pack by using a jumper wire connected to the kill wire coming out of the pack and shorting it to ground. If this kills the pack, the kill circuit in the harness or on the boat is bad, possibly the ignition switch.
Coils Only Fire with the Spark Plugs Out
- Check for a dragging starter or low battery causing slow cranking speed. DVA test the stator and trigger.
High Speed Miss
- DVA check stator voltage to each pack at high speed. If it exceeds 400 volts, replace the pack.
- Disconnect the rectifier. If the engine fires smoothly, replace the rectifier.
Two Cylinder Engines with Combination CD Module with Built-In Ignition Coils (1984-1988)
No Fire or Intermittent on One Cylinder
- Check stator resistance. You should read 680–800 ohms, with DVA 180V or more from blue to yellow. On some two cylinder engines, the stator has two blue wires and no yellow wire. In that case, the stator reads from blue to blue. All stator wires should read open to engine ground.
- Check trigger resistance. Trigger wire sets should read approximately 50 ohms between the wire sets (DVA 5V or more), and open to engine ground.
- If readings are good, disconnect the kill wire from one pack. If the dead cylinder starts firing, the problem is likely the blocking diode in the other pack.
Engine Will Not Kill
- Check the kill circuit in the pack by using a jumper wire connected to the kill wire coming out of the pack and shorting it to ground. If this kills the pack, the kill circuit in the harness or on the boat is bad, or possibly the ignition switch.