The distributor cap on mine was very brittle, likely original. New ones are available, but pricey. That’s the only issue mine had since I’ve owned it.
It also appears mine has had the wiring harness replaced at some point, too. My experience with other Mercs of that era is the wiring is in generally bad shape with the covering flaking off and the wire corroding. https://www.youtube.com/watch?v=P2_NAIXpT0E
Great motor in my opinion. The lower unit gear ratio is unique to that motor compared to other 6’s. I had one on a light weight 16′ Scatcraft for about 10 years. The boat flew and never let me down. Should have never sold it.