My port engine is making a loud clicking or popping sound above 4800 RPM. The motor does not seem to be missing or otherwise running bad and the exhaust note does not change. Any ideas?

Without hearing it its hard to tell.I did have one of the baffles come loose in my exhaust tips.It was rattling so bad thought I dropped a valve.
Clicking could be the shaft where is it trimmed?And does the sound change if you change trim.

No change with trim angle and only at the high end of the RPM range. Otherwise the motor is seems to be running just fine. Almost sounds like an electrical arc. We'll see what the dealer finds.

Pull your distrubuter caps off and inspect. They will show flowering on the contacts and rotor. Post pics of them.

You could possible have a bad spark plug, pull them all and read them. Sometimes you have to pull plug wires off while the motor is running to locate the bad plug? Plugs are cheap toss in a set and see if the problem stops, inspect the distributor cap and rotor while your at it. I have also heard of a little water in the tank causing the top end noise, pull your water seperators off dump them into a clear container and you will see immediately if you have a water problem. Post your findings! Good luck!

The dealer has been all over the motors and can't find a thing wrong, no error codes nothing. Looked at the ignition system as well and found nothing. Calls with both Formula and Mercruiser agree that if the motors are running strong, its not an internal issue with the motor but something external causing the noise.

The plan is to have the lead technician from Mercruiser (Jeff Dudome sp?) come to town to run the boat on the water in the spring and see if he can figure this out. I need to winterize this weekend and have the boat ready for storage by Oct. 1st.