2002 60hp 4 Stroke idle problem cyl #4l?

[GpaTom]

Boatmangc... Swapped the coils and still have a problem with #4 cly having a weak spark. Appreciate your advice as to what I can look at next.

As a History for others. I have a 2002 Mercury 4 stroke 60hp. At idle, #4 cly has a very weak spark causing a rough idle. When I bring up the rpms it appears to improve. Installed new plugs, no change, swapped the two coils, no change. Odd thing is that the coil for #4 also feeds cly #2 and #2 has no problem. Motor has about 40 + hours.

Thanks for all your advice and help.

[boats.net]

With those style coils if it has a spark then it is good. Your rough idle is a problem somewhere else. You might check fuel.

[GpaTom]

2002 60hp 4 stroke #4 cly idle problem

Thanks for responding. I do try and keep fresh premium fuel in the tank and have monitored and checked both fuel filters as well as the water seperator.

However it would be a good idea to double check again as you never know. My original thought was bad fuel or something in the #4 carb, but ruled this out when I discovered the low voltage on #4 cly.

Thanks again, will respond with what I find.
GpaTom

[nemobilemarine]

May be something you have thought of already, have you checked for bad grounds to the coils

[GpaTom]

2002 60hp 4 stroke #4 cly idle problem

Thanks, fuel is fresh and without tearing down the carb for #4, fuel seems fine. I will check grounds today (This is something I should have thought of, duh)
Thanks
GpaTom