Re: No spark on 82 merc
Hey guys im running a 1982 mercury 80hp. My problem is that my 1&2 Spark plugs are giving sparks my 3 is very weak and my 4 is not at all. Im not sure if this is a CDI issue or just leads or something else. Bought brand new plugs and still no success.
CDI Troubleshooting Guide
Shortcut:
Mercury 4 Cylinder
Follow the steps under "NO SPARK OR INTERMITTENT SPARK ON ONE OR MORE CYLINDERS", specifically:
(Note) If #1 and #2, or #3 and #4 are misfiring, check the trigger as described above. The trigger has two coils firing four cylinders. #1 & 2 share a trigger coil and #3 & 4 share a trigger coil. Also, the switch box is divided into two parts. The #1 and #2 cylinders spark on one side and #3 and #4 spark from the other side of the switch box. If the trigger tests are okay according to the chart above, but you have two cylinders not firing (either #1 and #2, or #3 and #4), the switch box or stator is bad.
2. If you have two cylinders not firing (either #1 and #2, or #3 and #4), switch the stator leads end to end on the switch box (swap Red with Red/White) and (swap Blue with Blue/White). If the problem moves to the other cylinders, the stator is bad. It the problem stayed on the same cylinders, the switch box is likely bad.
Resistance is a highly unreliable measurement. DVA is a highly accurate measurement.
One must have a
DVA Adapter plugged into a
digital meter to accurately read DVA (peak AC voltage) on an outboard. No digital meter on the market has built-in DVA.
DVA Explained
If purchasing DVA equipment is impractical, we suggest printing off the troubleshooting pages & taking them & your engine to a qualified marine mechanic.
