I have a 98 Ocean Pro and the Link and Sync procedure can be performed yourself, but I strongly recommend you buy an OMC shop manual for that motor to do it. It takes you step by step through the procedure. (If its running now as good as you describe, you may not even need to do it) Fortunately, if you're not confident enough to do this, any Evinrude and or Johnson tech will know how.
But before you do that, run a couple of cans of Sea Foam when the fuel tank level is low, and that should certainly clean out your carbs and remove any carbon or coking on your pistons. My Ocean Pro responded well to this. Run the engine normally for about 20 minutes then shut it down. Let the Sea Foam soften the carb deposits and crud in your low speed (idling) jets. Then start her back up. She may smoke like crazy, but you're just burning off the loosened carbon and crud in the cylinders and carb jets. Its an easy thing to to do before tearing into the linkages.
These particular engines have to be de-carbinized at least once a year
You can use Sea Foam or BRP Engine Tuner. There is also a Schrader valve on your engine to ingest the Engine Tuner directly into your engine when running.
As for your compression, its fine. The general rule of thumb is that when all 6 cans are pulling within 80% compression of each other, your powerhead is fine. This is even stated in the OMC shop Manual I have.
You also seem to be propped with a little to much pitch, that motor should be turning 5500 -5700 rpm at WOT.
