86 90HP Merc 6cyl. running issues.

[xcspxlt]

A little history on this motor and what we have done so far.
The boat and motor have been sitting for almost 18 years. changed fuel filter and fuel hose, cleaned tank and started with fresh gas and oil. It would start and run but only above 1500 RPMs. Found we had no spark on #one cylinder and week spark on #4. verified the problem was the switch boxes and replaced both with new. Runs better but still have issues. Spark on all 6 seems good some of the time but them will drop out. noticed today that there seemed to be a lot of ticking noise around the coils.
I removed the 2 coil packs of three and insulated them from mounting. It ran much better and actually got it down to idle for a while. However I am still getting some ticking noise from coils for 1-3 even though they are an inch from any metal. The lower 3 for cyl 4-6 only tick now when installed back on the mounting plate.
Resistance checks on the coils does show that #1 has a high impedance from primary to output, all the rest are within spec. Is it possible that these coils are shorting themselves to ground when not even mounted?
Thanks for any ideas or suggestions you have.

 

[Chris1956]

Mercury ADI ignition systems have a low speed and high speed stator coils. You might om them out to see if the low speed stator winding is good.

Ticking noises can be arc to ground. Maybe spark plug wires are bad?

 

[xcspxlt]

Thanks for the reply Chris,
The ticking is definitely coming from the coils. The three that tick when not mounted are fairly quite. When the packs are mounted to the plate the ticking is very loud. I even put another 1/15th inch of rubber under the coil packs when mounted and they still tick like they are arcing somewhere. Cannot see the arcing wither.
Stator coils have been ohm'd and are within spec. spark plug wires are 0 ohms and in good shape. Ordered new coil packs and they will be in on Monday or Tuesday. Also waiting for a DVA adapter and will do some measurements when that gets here.