2002 60hp 4 Stroke Bad Coil?

[GpaTom]

First time on forum. I have a 2002 60hp 4 Stroke Merc. At idle, cyl #4 indicates low voltage due to weak spark when pulling a plug wire. Cyl's 1-3 show nice hot spark when pulling their plug wires. Replaced with new plugs and still had same problem. Spark does seem to be better (more even) when running at higher RPM. Can't swap plug wires as they are molded into coils. Motor has approximately 40 hours total run time. Gas is fresh premium grade. Any help is greatly appreciated.
Thanks

Additional info: Cyl #2 and #4 are fed from the same coil. while I am noticing a weak spark on #4 at idle, Cyl#2 seems okay. Any info on what the cause may be and how to test for it is greatly appreciated.
Thanks again
GpaTom

[boats.net]

Yes a bad coil can cause weak spark.

[GpaTom]

2002 60hp 4 Stroke Merc Bad Coil?

Do you know how I can check/test the coil to see if it is bad or ok? Thanks for responding

[boats.net]

You will need to obtain a service manual.

[GpaTom]

2002 60hp 4 Stroke Merc Bad Coil?

Thanks for the responce. I'll see if I can't locate one.

[boatmangc]

Switch the 2 coils and see if the problem follows the coil or stays with the cylinder

[GpaTom]

2002 60hp 4 Stroke Merc Bad Coil?

Thanks, will give it a try.

[GpaTom]

2002 60hp 4 Stroke Merc Bad Coil?

Boatmangc, Swapped the coils and the problem stays with the cylinder. Any other ideas that I can try? I appreciate all the help.